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Linux Gazette... making Linux just a little more fun!
Copyright © 1996-97 Specialized Systems Consultants, Inc. linux@ssc.com
______________________________________________________________________________________
Welcome to Linux Gazette! (tm)
Linux Gazette, a member of the Linux Documentation Project, is an on-line WWW publication
that is dedicated to two simple ideas:
* Making Linux just a little more fun
* Sharing ideas and discoveries
The basic idea behind these two concepts is that Linux is one cool OS, whose price for
admission is a willingness to read, learn, tinker (aka, hack!), and then share your
experiences. The Gazette is a compilation of basic tips, tricks, suggestions, ideas and
short articles about Linux designed to make using Linux fun and easy. LG began as a
personal project of John M. Fisk, and grew to include contributions freely provided by a
growing number of authors. Linux Journal is now publishing the Gazette using material
contributed by outside authors (note to potential authors). Without these authors there
would not be a Gazette, and I thank them all. Drop a note to the author of anything that
you find helpful or instructive--the author's e-mail address is included for this very
purpose.
Linux Gazette is a non-commercial publication and will remain that way. A tar, gzip file
containing all issues of Linux Gazette and one containing the current issue can be found at
ftp://ftp.ssc.com/pub/lg/
Thanks to Matt Welsh, coordinator of the Linux Documentation Project, for graciously
bringing the Linux Gazette under the auspices of the LDP. The material included in these
documents is covered by a designedly liberal copyright. For information regarding copying
and distribution of this material read the Copying License.
A new table of contents will appear with each issue that will allow you to easily find
articles of interest. A search engine is also provided to allow you to search all issues
for items relating to a particular subject.
Have fun!
______________________________________________________________________________________
* Table of Contents Issue #14
* Table of Contents Issue #13
* Table of Contents Issue #12
* Table of Contents Issue #11
* Table of Contents Issue #10
* Table of Contents Issue #9
* Table of Contents Issues #1-#8
* Index of All Issues
______________________________________________________________________________________
Search In: [Linux Gazette (TM).......]
Search For: ______________________________ ______
______________________________________________________________________________________
Linux Gazette WWW & FTP Mirror Sites
For those readers who are accessing Linux Gazette from outside the U.S. or are having
problems with slow connections at a particular site, mirror sites are available worldwide.
Thanks to all of the people who have kindly offered the use of their WWW and FTP sites in
order to make this possible!
______________________________________________________________________________________
[ Hot Linux News! ] [ Linux Resources ]
Two SSC links that you might find useful. The first is to Linux Journal 's "Hot Linux
News" page, and the second is to SSC's Linux Resources page.
______________________________________________________________________________________
LINUX GAZETTE IS PUBLISHED BY:
SSC - Publishers of Linux Journal (tm)
______________________________________________________________________________________
Got any great ideas for improvements! Send your comments, criticisms, suggestions and
ideas.
Linux Gazette, http://www.ssc.com/lg/
This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com
[IMAGE]
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
The Mailbag!
Write the Gazette at gazette@ssc.com
CONTENTS:
* Help Wanted -- Article Ideas
* General Mail
[IMAGE]
______________________________________________________________________________________
HELP WANTED -- ARTICLE IDEAS
______________________________________________________________________________________
Date: Mon, 20 Jan 97 13:22:54 EST
Subject: Linux on Compaq
From: afarnsworth@S1.DRC.COM
Hi,
I just received a brand spanking new Compaq Deskpro 6000 with Adaptec 2940U SCSI card and
Compaq Netflex III ethernet card. I think I have the SCSI card problem whipped, but how do
I find drivers for the Netflex III card? I have check the usual places, does it even exist?
The Compaq Deskpro 6000 is a fairly new system out, though Compaq has been building
Deskpro's for many years. The only problem I have had with them is their proprietary
hardware. This is usually either their Network cards or their Hard drive controllers
(usually RAID controllers). Other than that, it's pretty standard.
Please reply to my email address : afarnsworth@s1.drc.com for I don't have the ability to
check the gazette often. Thanks.
Andy Farnsworth, Dynamics Research Corporation
______________________________________________________________________________________
Date: Sat, 18 Jan 1997 12:38:45 +0200 (EET)
Subject: Office-tools From: J.Hernetkoski, jjjj@zenith.yok.utu.fi
Hi! Could you write an article about these two office-package for Linux:
* Applixware
* StarOffice
Thanks
Jukka Hernetkoski
(An article about StarOffice by Dwight Johnson appeared in issue 9 of Linux Gazette. An
article about Applixware will be in the April issue of Linux Journal. I can probably get
permission to run it in LG also, but not until that issue of LJ is on the stands. Which
means it would also be the April issue of LG. Anyone want to do one sooner?--Editor)
______________________________________________________________________________________
Date: Tue, 21 Jan 1997 09:43:58 -0500
Subject: Linux samba win95
From: nravin@cs.fit.edu
-I am a system administrator....manages 20 PC's....all running windows95
-We were running Windows NT server(4.0) in the lab for some time Then we realised we had
only 10 client access licenses and so were forced tp SWITCH to Linux.
-Linux emulates NT, as you may know
-I had the CONFIG.POL working perfectly with the NT network. -But when I switched to Linux
I lost that control. No longer are the clients able to access the CONFIG.POL file even
though I have kept it in the NETLOGON share.
-Now whosoever uses the PC's(most are novices) play around with the settings( of client)
and is giving me nightmares, since I cannot lock them out.
-Is there a way out? How can I make the clients read the system policies from the
CONFIG.POL using Linux server?
Please help.
Thanks
Neal
______________________________________________________________________________________
Date: Tue, 21 Jan 1997 15:03:07 +0000
Subject: dbms connectivity
From: Mike Lewis, mlewis@burly.com
Hi. I love linux but most of the projects I work on preclude it because of a lack of dbms
connectivity. None of the major dbms players (Oracle, Sybase, Informix, etc.) or 3rd party
developers (Intersolv, Visigenic, etc.) offer access from a linux client. I've tried a
middleware solution from Openlink and I guess you could run SCO drivers with emulation,
assuming you can get your hands on the low-level libraries.
This seems to be the only thing standing in the way of Linux getting business worthy
respect. Could you put together a piece on this issue and explore the future availability
of dbms connectivity from linux?
Thanks.
Mike
______________________________________________________________________________________
Date: Wed, 22 Jan 1997 18:21:57 -0800
Subject: X Windows & Unix
From: Nestor Villalobos, n.villalobos@codetel.net.do
Hi there! I just got Linux from RedHat and I have been wondering how to do Animations in
XWindows. I would like a little picture box on the lower right hand corner of the screen on
startup to start an animation. Is this possible? If it is, please email me back with
instructions!!! Thanks for the help.
One Unix man to the other,
Nestor Villalobos
[IMAGE]
______________________________________________________________________________________
GENERAL MAIL
______________________________________________________________________________________
Date: Fri, 24 Jan 1997 15:24:16 -0700
Subject: Update web link in my article
From: Henry Lu, honglu@rt66.com
I have changed my web page (email is unchanged). Can you update my web page in the #10
issue, article "setting up a Dynamic web server"?
http://www.tc.umn.edu/nlhome/g625/luxx0024/
I got couple of email inquiry about the bad link.
Henry
(Be happy to fix it up. We like to stay up to date. --Editor)
______________________________________________________________________________________
Date: Tue, 21 Jan 1997 13:20:49 -0700
Subject: C++ Programming w/ Linux
From: James Cannon, cannonj@jads.kirtland.af.mil
Hi,
About a month ago I asked about help with C++ programming on Linux. I am currently using
the Walnut Creek Slackware, kernel 1.3.20. I had a hard time getting a simple "Hello World"
program to compile. "cc" couldn't find the ".h" files like "stdio.h", which are normally in
/usr/include. I had to create a "$INCLUDE" variable in my ".profile". So, when compiling, I
used "g++ -I $INCLUDE -o hello hello.c" to compile.
Well, I received help via e-mail pointing me to this page:
phttp://www.cuug.ab.ca:8001/~barkers/slackware-fixes/3.0-fixes.html
Look for the section titled: Problem Using G++.
Great mag!
James Cannon, http://www.jads.abq.com/
______________________________________________________________________________________
Date: Thu, 23 Jan 1997 20:36:39 -0800
Subject: Color Depths in X
From: Chris Spiegel, matrix@wolfenet.com
(RE: Color depths in X)
Well, I know this isn't really a fix, and it's not that great, but I have 2 scripts. startx
which starts me in 16 bit color and start8, which starts in 8 bit. As I said, not a
solution, but a pretty painless alternative...
______________________________________________________________________________________
Date: Fri, 3 Jan 1997 17:14:19 -0500 (EST)
Subject: Further note about the spiral notebook page design.
From: Ben Boule, bouleb@rpi.edu
Someone else noted that his web browser didn't correctly show the spiral notebook
background. I use Netscape, so that isn't a problem for me, but I do have another problem
with the background. It's very hard to look at on an interlaced display. I can always
switch to a non-interlaced mode in XFree86, but I'd bet some people can't. I know that the
interlaced mode that I use looks fine on 99.99% of web pages, so it usually isn't a problem
for me.
Thanks,
Ben Boule
______________________________________________________________________________________
Date: Mon, 06 Jan 1997 13:42:25 -0600
Subject: RE: Linux networking problem with VINES
From: Jack N. Gallemore, jgallemore@okokc.ang.af.mil
To: Stephen, Tauche%fbm%mfh@mfhdvzis.mfh-iserlohn.de
Unfortunately, Banyan is a pretty tight (read: won't work with much) OS, so you are pretty
limited. There is a way for Linux to sign onto Banyan, but you have to use DOSEMU.60.1. The
later versions will not work. (Disclaimer: I have not used the patch for dosemu.60.4). If
you have not used DOSEMU, the setup is fairly straightforward.
As for using Linux as a resource, you will have to use IP stuff (ftp, telnet, etc) to do
so. There are no ports for LinuxBanyan stuff.
BTW, Jon is still doing Linux and Banyan. His site (http://www.netmind.com) is running
Linux! Check it out!
Jack N. Gallemore jgallemore@okokc.ang.af.mil
______________________________________________________________________________________
Date: Mon, 20 Jan 97 16:12:00 PST
Subject: Vines IP and TCP/IP
From: Denis Dimick, ddimick@irvine.ddddf.com
Back on Dec 5, 1996 Stefan wrote wanting help with Vines.
**************************************************************
Stefan the problem you're having sounds like the Vines Servers are not passing TCP/IP.. By
default Banyan Vines doesn't pass route TCP/IP thru the servers. You have to have the
TCP/IP option installed on all the servers your going to route thru. This option cost $$$
about $1200.00 US if I remember correctly. So there's p[robally a good chance your school
didn't buy this option...
Vines doesn't have anything that will cause IP to tunnel via Vines IP.. So your only chance
might be to get access to the same segment that the internet is running off of... But it
sounds like your sysadmin is using the Banyan Server as the gateway to the internet, if
this is the case your out of luck...
Since I've worked with Banyan Vines for the last 7 years, I'm sorry to say you might not be
able to set up the Linux Box on the internet routing thru your Banyan Servers...
Denis, dgdimick@sure.net
______________________________________________________________________________________
Date: Sat, 11 Jan 1997 11:49:18 -0700
Subject: Linux Applications and Utilities Page
From: David Puryear, dayear@market1.com
Hi,
I came across Linux Applications and Utilities Page while I was learning about linux. It
helped me get the feel for what is able in linux.
http://www.xnet.com/%7Eblatura/linapps.shtml
The guy that maintains it is Bill Latura. I hope people will get good use out of it and
maybe help it become even more complete:)
David
(We found it too; see News Bytes. --Editor)
______________________________________________________________________________________
Date: Tue, 14 Jan 1997 06:06:09 -0800
Subject: isssue 8 & ftp server
From: Rick Lim, rick_lim@bc.sympatico.ca
Hi there,
thanks for hosting the gazette. Is there a way of just downloading the text of each issue?
I have downloaded LinuxGazette_jan97.tar.gz and it seems that issue8.txt is missing. also I
have tried to ftp LinuxGazette_dec96.tar.gz but after 1770k of 2751k the server seemingly
goes into ignore mode, this has happened about 5 times.
Thanks again
rick
(Don't know why you are having trouble ftp'ing LinuxGazette_dec96.tar.gz, but can tell
you that you have LinuxGazette_jan97.tar.gz you have everything that is in dec96. We
took over LG for issue 9, so there is no file issue8.txt or 1 to 7 either. We use Lynx
to save the HTML as text. Perhaps we'll do it for 1-8 one day when we have time.
--Editor)
______________________________________________________________________________________
Date: Sun, 26 Jan 1997 17:00:35 -0600
Subject: suggestion
From: dave Stephens, ts@fuzzy4u.com
can you put some thing in each week for the new linux ueser the newbe things
thank you
Dave
(LG is posted once a month not weekly. All the material in LG is contributed to me by
outside authors. I take whatever I get. A lot of it is geared toward the newbee, and
this month we have a new column called "Clueless At the Prompt" by Mike List that is
designed for the newbee. Sounds like just what you are looking for. --Editor)
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Next
This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com
Copyright © 1997 Specialized Systems Consultants, Inc.
[IMAGE]
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
MORE 2<> TIPS!
Send Linux Tips and Tricks to gazette@ssc.com
______________________________________________________________________________________
CONTENTS:
* Backquote Warning
* Browser Background Tip
* Even Better Lowercasing of Filenames
* Filtering Advertisements from WWW Tip
* Getting Less to View gzipped Files
* Help for Help on the Bash Shell
* Lower Your Caps
* Making Linux Boot Floppies
* More on Xterm Titlebar
* Remind Tip
* Script to Call Your Editor
* Tip for Your Web Page
* Titlebar Tip
* 2 Bit Tip -- Heartbeat
* 2 Cent Tip for xdm
* Two 2 Cent Tips -- syslog & X Color Depth
* X Windows Depth
______________________________________________________________________________________
[IMAGE]
BACKQUOTES WARNING
Date: Tue, 14 Jan 1997 00:40:21 -0800 From: alan bailward
In the $0.02 tip for using the script 'swaplogs' the commands : cp /var/adm/messages
/var/adm/messages.'date +%d' uses the wrong quotes. The backquote not the forward quote has
to be used here, to make the *output* of the command part of the filename.
alan
(Actually, the backquote is in the html. It's just that some Browser fonts wont print a
backquote -- in fact, mine doesn't. I'm not sure how to get around this other than to
warn people who are reading online. If you print LG out, the quotes will be in the right
direction. --Editor)
______________________________________________________________________________________
[IMAGE]
WWW BACKGROUND TIP
Date: Wed, 8 Jan 1997 12:23:03 -0500 (EST)
From: Kurt M. Hockenbury, kmh@linux.stevens-tech.edu
I noticed people complaining about backgrounds making text unreadable. Personally, I got
tired of unreadable backgrounds, as well as large image downloads, so I turned them off. I
also turned off those annoying blink tags.
How? Add these two lines to your ~/.Xdefaults file.
Netscape*documentColorsHavePriority: False
Netscape*blinkingEnabled: False
In LG #13, Eje Gustafsson, gne@ffa.se writes:
>> 1.mv /var/adm/messages /var/adm/messages.prev
>> 2.touch /var/adm/messages
>> 3.kill -1 pid-of-syslogd
>>
>> This should work on a decent Unix(like) system, and I know Linux
>>is one of them.
>
>This is NOT an proper way of truncate /var/adm/messages.
>
>It is better to do:
>
> 1.cp /var/adm/messages /var/adm/messages.prev
> 2.>/var/adm/messages or cp /dev/null /var/adm/messages (both of them makes
>the file empty).
> 3.No more.
I'm sorry, but (at least on Linux) this is flat out _wrong_. The first method (mv & HUP) is
the correct method of truncating syslog files (such as /var/adm/messages).
Your method looses any messages that get syslog'd between steps 1 and 2; anything that
comes in after the first cp gets overwritten when the second cp happens.
>The problem is that when you remove the /var/adm/messages syslogd gets
>confused and unhappy and you have to give syslogd a HUPSIG but if you
>just sets the file length to zero without removing the file syslogd
>don't complain. And if you are really unlucky your system will go down
>because you didn't create /var/adm/messages quick enough or forgot it.
Not so. mv'ing /var/adm/messages doesn't bother syslogd at all, as long as you stay on the
same partition. In fact, you can 'mv /var/adm/messages /var/adm/fish', and until syslogd is
HUP'd or otherwise restarted, it will keep logging in the file fish. Try it if you don't
believe me - it's true! That is because once syslogd has open()d the file, it will keep
writing to that file until it close()s it - and a file in the Unix world is an inode, not a
filename. (As an aside, this is how you can have the 100% full empty partition. Even though
you unlink or rm a file, the file doesn't actually go away until all programs that have it
open close it.)
syslogd doesn't get confused at all. You can even rm /var/adm/messages, and syslogd won't
crash your system, though eventually the partition may fill up with syslog messages you
can't easily read since there isn't a filename associated with the log file anymore.
Kurt Hockenbury, Distributed Systems Administrator
Stevens Institute of Technology
______________________________________________________________________________________
[IMAGE]
EVEN BETTER LOWERCASING OF FILENAMES
Date: Sun, 5 Jan 1997 19:17:16 -0800 (PST) From: Greg Badros, gjb@cs.washington.edu
It's even easier with zsh (3.0.x) to convert filenames to all-lowercase:
for i in *(.); mv $i ${i:l}
The *(.) uses a modifier on the wildcard to mean "only regular files" (i.e., not
directories). And the ${i:l} converts the variable to lowercase, so we don't have to use
tr.
This is not only shorter to type, but doesn't exec multiple programs (test + mv + tr) for
each file, and looks at fewer files since the shell implicitly does the first test.
Greg
______________________________________________________________________________________
[IMAGE]
FILTERING ADVERTISEMENTS FROM WEB PAGES USING WEBFILTER
Date: Thu, 16 Jan 97 20:28:50 PST
From: Axel Boldt, boldt@cardinal.math.ucsb.edu
Hi, In last month's Gazette, David Rudder wrote an article about how to filter
advertisements from web pages using IPFWADM, the idea being that many ads come from the
same site and it is easy to configure a Linux firewall to refuse all connections from such
a site.
This approach has two disadvantages: you have to be root in order to use the IPFWADM tool,
and it allows you only to block entire sites. Very often, you want to filter out only a
specific ad residing on a site, without blocking the rest of that site's material.
Moreover, different users of the Linux box might have different tastes when it comes to
ads.
I believe that my tool WebFilter a.k.a. NoShit addresses these issues and is better suited
for filtering ads from specific web sites. The idea is the following: the user runs
WebFilter as a personal filtering proxy server, and the browser contacts this proxy
whenever it wants to fetch a web document. The proxy then actually goes out and downloads
the page, checks whether any filterscripts apply to this page, and if yes, pipes it through
those scripts and returns the output to the browser. The mapping between URL and
filterscript has to be provided by the user in advance. A filterscript can be an arbitrary
program that reads the original document from standard input and produces the filtered
version on standard output. In practice, filterscripts are most often short sed, awk, or
perl scripts.
If you often use sites such as Yahoo or Infoseek, you can easily write filterscripts that
excise the ads from their pages. This saves time, money, and bandwidth.
More information about WebFilter can be gotten from its homepage. There you'll also find
links to other programs implementing the same idea.
Have fun,
Axel
______________________________________________________________________________________
[IMAGE]
GETTING LESS TO VIEW GZIPPED FILES
Date: 09 Jan 1997 20:18:58 -0600
From: Alan Shutko, ats@wydo125.wustl.edu
A little known ability of less is the ability to define filters when it opens and closes
files. This excerpt from the man page deserves broader attention, since it can easily be
extended to other types.
For example, on many Unix systems, these two scripts will allow you to keep files in
compressed format, but still let less view them directly:
lessopen.sh:
#! /bin/sh
case "$1" in
*.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
if [ -s /tmp/less.$$ ]; then
echo /tmp/less.$$
else
rm -f /tmp/less.$$
fi
;;
Version 321: 18 Jul 96 16
esac
lessclose.sh:
#! /bin/sh
rm $2
To use these scripts, put them both where they can be exe- cuted and set
LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More complex LESSOPEN and
LESSCLOSE scripts may be written to accept other types of compressed files, and so on.
Alan Shutko
______________________________________________________________________________________
[IMAGE]
HELP FOR HELP ON THE BASH SHELL
Date: Tue, 14 Jan 1997 15:36:50 +0100 (NFT)
From: mailto:fk5a005@math.uni-hamburg.de
you did hear about help for the bash. if you invoke help for then you will get some help
about for.
Okay, you know that one. But did you know you can see all the helps at once? I did not know
it. Then I tried help "$*" and what happend was: every help was shown! Of course too much
for one screen. so I piped it to less: help "$*" |less is quite good. But then I thought
about having a search command with less. possible? yes, just do a less -p word file to see
it.
So I put everything together and like I do often I created an alias:
alias helpall="help '$*' | less -p "
and tried it: beautiful, I might not need man bash all the times. Try it yourself.
Perhaps try helpall " let " to see a result.
Have a nice and bright Linux-year!
Matthias
______________________________________________________________________________________
[IMAGE]
LOWER YOUR CAPS
Date: Sat, 25 Jan 1997 20:44:42 -0800 (PST)
From: Peat Bakke, pb@europa.com
One of those little things that gets to me is unzipping DOS pkzipped files. All of the
filenames are in all caps. I'm not sure why it bugs me, but it does. Anyhow, here's a quick
script that I've found useful to convert all the caps in a directory into lower case
(rather nice when you've got one of those big, 200 file zips):
#!/bin/tcsh
foreach i (*)
mv $1 `echo $1 | tr '[A-Z]' '[a-z]'`
A word to the wise -- this lowers ALL caps, so be careful with those Makefiles and such.
-Peat
______________________________________________________________________________________
[IMAGE]
MAKING LINUX BOOT FLOPPIES
Date: Sun, 5 Jan 1997 18:40:49 -0800 (PST)
From: Andy Kahn, kahn@vivian.cs.ucla.edu
After reading Bill Duncan's excellent article in issue #13 on using and managing floppies
in Linux, I figured I'd toss in a 2-cent tip.
Here is a script I use to make emergency boot floppies on my system (kernel v2.0.27). The
need arose when I installed RedHat 4.0 for the first time and noticed that the installation
procedure doesn't automatically prompt you to create boot floppies (Slackware does, and
chances are that RedHat will also in the next version).
#!/bin/csh -f
#
# makebootfloppy v0.2
#
# DESCRIPTION:
# User friendly script (with lots of verbose messages) used to make
# Linux boot floppies, using the 2.x kernels.
#
# Formats, creates the file system, mounts the floppy, installs the Linux
# kernel, installs LILO, umounts floppy, and cleans up.
#
stty intr
set PATH=(/usr/sbin /sbin /bin /usr/bin)
# the generic floppy device (usually auto-detected)
set GENFLOPPY=/dev/fd0
# the low-level floppy device, used with fdformat. this might be obsoleted
# on your system
set LLFLOPPY=/dev/fd0H1440
# a temporary mount point for your floppy. make sure it has enough space
# to copy the kernel into
set MOUNTPOINT=/tmp/floppy
# boot
set BOOT=/boot/boot.b
set KERNEL=/boot/vmlinuz
# LILO label
set LABEL=linux
# here we go!
#############
echo -n Insert a blank floppy into the drive and hit return...
set FOO=$& /dev/null
mount $GENFLOPPY $MOUNTPOINT
# Copy the kernel to the floppy
cp $BOOT $MOUNTPOINT
cp $KERNEL $MOUNTPOINT
# Install lilo
echo image=$MOUNTPOINT/`basename $KERNEL` label=$LABEL | \
lilo -C - -b $GENFLOPPY -i $MOUNTPOINT/boot.b -c -m $MOUNTPOINT/map
sync
# Unmount floppy
umount $MOUNTPOINT
# Deleting temporary mount point
rm -rf $MOUNTPOINT
echo All done.
______________________________________________________________________________________
There's currently no error handling, so if one command fails, the remaining commands will
fail as well. Other than that, feel free to modify and use it as you like. If you have
suggestions on better ways to do something, I'd love to hear them.
--Andy, kahn@cs.ucla.edu
______________________________________________________________________________________
[IMAGE]
MORE ON XTERM TITLEBAR TIP
Date: Wed, 15 Jan 1997 23:33:34 -0700 (MST)
From: Michael J. Hammel, mjhammel@csn.net
I got a lot of email about my tip, most confused by the use of escape/control characters
in the script. Here is my response.
> > Date: Sat, 21 Dec 1996 15:18:01 -0600
> > From: Roger Booth
> > To: Linux Journal Editor
> >
> > The Jan97 Issue 33 of Linux Journal contained the "Linux Gazette Two Cent Tips".
> > I was interested in the tip "X Term Titlebar Function". Although
> > the text of the tip stated that the tip would work in ksh-based
> > systems, I could not get it to work as shown. I think there are
> > three problems. First, I think there are a few transcription
> > errors in the script. Second, I believe the author is using
I don't think there were transcription problems. I'm pretty sure it was the way I sent it,
however....
> > embedded control characters and it was not obvious to me which
> > character sequences are representations of control characters
> > and which characters should be typed verbatim. Third, the
Yes, there were control and escape characters in the file. This was a problem and many
people wrote me to ask about it. In the following lines:
ilabel () { echo -n "^[]1;$*^G"; }
label () { echo -n "^[]2;$*^G"; }
the characters "^[" are an escape character and the characters "^G" are a CONTROL-G
character. In order to add these to your file (when you type it in by hand) using vi you
would type:
^VESC - which means CTRL-SHIFT-V followed by the ESCAPE key
and
^V^G - which means CTRL-SHIFT-V followed by CTRL-SHIFT-G
Note that in *this* email I didn't actually include the control or escape characters - I
simply used their ASCII equivalents. Hopefully this isn't too confusing.
> > author uses a command-line option to the echo command which
> > is not available on all Unix platforms.
This is also a problem. See below.
> > I finally used the following script:
> >
> > if [ ${SHELL##/*/} = "ksh" ] ; then
> > if [[ $TERM = x"term" ]] ; then
> > HOSTNAME=`uname -n`
> > label () { echo "\\033]2;$*\\007\\c"; }
> > alias stripe='label $LOGNAME on $HOSTNAME - ${PWD#$HOME/}'
> > cds () { "cd" $*; eval stripe; }
> > alias cd=cds
> > eval stripe
> > fi
> > fi
> > I don't use vi, so I left out that functionality.
I tried this and various similar responses that were mailed directly to me. It should work
using the octal versions of the escape sequences, but I couldn't get it to work. My
problem is that I use the label() function from the command line at times to simply set
the title bar to some arbitrary value and using the octal sequences didn't seem to work
for me. I'm not sure why, however. I do believe that, sometime in the distant past, I too
used octal sequences to set the xterm title bar. I've long forgotten why I switched.
> > The functional changes I made are all in the arguments to the
> > echo command. The changes are to use \\033 rather than what
> > was shown in the original tip as ^[, to use \\007 rather than
> > ^G, and to terminate the string with \\c rather than use the
> > option -n.
All of these should work just fine in ksh. Your observation that not all shells accept
"echo -n" is correct. I often have to check which works and then manually set the echo
line to either use "-n" or to print a \c. One or the other will always work, depending on
if the echo is a shell builtin or an actual Unix command.
> > On AIX 4.1, the command "echo -n hi" echoes "-n hi"; in other
> > words, -n is not a portable command-line option to the echo
> > command. I tested the above script on AIX 3.2, AIX 4.1,
> > HPUX 9.0, HPUX 10.0, Solaris 2.4 and Solaris 2.5. I'm still
> > trying to get Linux and my Wintel box mutually configured,
> > so I haven't tested it on Linux.
I don't use X on the AIX or HPUX boxes at work. I just rlogin from my Sun boxes. However,
both Solaris and Linux should work with the -n option if you're using the echo shell
builtin. If not, the \c will probably be required. On my Linux box I type
bash% type echo
which reports
echo is a shell builtin
so I know which one I'm using. Knowing this you can provide alternatives within your
.bashrc or .kshrc to determine which version of the echo line to use. This is true of any
Unix platform on which you use ksh or bash (I believe).
> > I have noticed a problem with this script. I use the rlogin
> > command to log in to a remote box. When I exit from the
> > remote box, the caption is not updated, and still shows the
> > hostname and path that was valid just before I exited. I tried
> > adding
> >
> > exits () { "exit" $*; eval stripe; }
> > alias exit=exits
> >
> > and
> >
> > rlogins () { "rlogin" $*; eval stripe; }
> > alias rlogin=rlogins
> >
> > Neither addition updated the caption to the host/path
> > returned to. Any suggestions?
Add this right after the alias for cd in the original script:
rlogins () { "rlogin" $*; cds . }
alias rlogin=rlogins
Its a hack, but it works. You have to use "cds" instead of the alias "cd" or else the real
cd gets used and the title bar won't change. In case anyone is wondering, the reason you
enclose "rlogin" (or "cd" or "vi") in double quotes in this script is so the function
rlogins() will run the real rlogin and not get stuck recursively calling itself. Neat, eh?
Boy, this stuff could get confusing fast. Maybe it wasn't such a good tip after all.
Michael J. Hammel
______________________________________________________________________________________
[IMAGE]
REMIND TIP
Date: Mon, 20 Jan 97 15:42:04 PST
From: jmy@gim.net
This is a nice little script wich I have made, it places reminders to ~/.tcshrc or
whatever. I think it's very useful. To use it first place at THE END OF ~/.tcshrc:
\echo
echo "--------------------( R E M I N D E R S )--------------------"
echo "-------------------------------------------------------------";\echo
Then use this script:
------------------------------c-u-t--h-e-r-e-------------------------------
#!/bin/tcsh
# Nice little scipt that places reminders to the end of ~/.tcshrc or
whatever.
# Made by jmy@gim.net email if you like it!
echo Remind 1.0 by jmy@gim.net
if ($#argv == 0) then
echo Use like \'remind \ \\'
echo Option is \'a\' for add , \'u\' for undo and \'r\' for remove, pretty
easy
huh..:\)
\echo
echo NOTE: IF YOU REMOVED A LINE YOU DIDN\'T MEAN TO REMOVE, USE UNDO\!
\echo
exit 666
endif
if ($argv[1] == a) then
cat ~/.tcshrc | awk '\!/-------\";\\echo/ { print }' >! /tmp/remind.$user
echo echo $argv[2-] >> /tmp/remind.$user
echo 'echo "-------------------------------------------------------------";\echo'
>> /tmp/remind.$user
cp ~/.tcshrc ~/.tcshrc.remind
rm -f ~/.tcshrc
mv /tmp/remind.$user ~/.tcshrc
echo Added reminder: $argv[2-]
else if ($argv[1] == r) then
cat ~/.tcshrc | grep -v "echo $argv[2-]" >! /tmp/remind.$user
cp ~/.tcshrc ~/.tcshrc.remind
rm -f ~/.tcshrc
mv /tmp/remind.$user ~/.tcshrc
echo Removed Reminders:
diff ~/.tcshrc ~/.tcshrc.remind | awk '$2 ~ /echo/ { print$3,$4,$5,$6,$7,$8,$9,
$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21,$22,$23,$24,$25 }'
else if ($argv[1] == u) then
if (-e ~/.tcshrc.remind) then
mv ~/.tcshrc ~/.tcshrc.remtemp
mv ~/.tcshrc.remind ~/.tcshrc
mv ~/.tcshrc.remtemp ~/.tcshrc.remind
echo Undo completed
else
echo No undo file was found \(~/.tcshrc\)
endif
else
echo Error: invalid argument\(s\) run it with no argument for a short help
\echo
exit 666
endif
\echo
---------------------c-u-t--h-e-r-e--a-l-s-o------------------------------
Dont forget to do a 'chmod a+x remind' And NEVER place any new lines after the lines you
placed in ~/.tcshrc If you wan't to use it with some other shell it should just be like
changing the paths in the script. And yes, it maybe should have been alot easier to put
the reminders in a separat file, but i like this solution i'ts alot cooler...and maybe it
can show someone how awk works.
______________________________________________________________________________________
[IMAGE]
SCRIPT TO CALL YOUR EDITOR
Date: Thu, 16 Jan 97 15:21:34 PST
From: Gary Chambers, geecee@gwi.net
I just found the Linux Gazette... Thankfully! It has truly made using Linux more fun.
I use the Linux version of Marko Macek's FTE editor. Since it is comprised of a separate X
and console version, I began to get frustrated with having to manually specify a default
editor. Now, wherever I can specify it (e.g. Pine), I use my edit script. It also provides
similar functionality at the command line.
I'm new to Linux, so there may be better ways of doing this. I submitted this for
inclusion in your 2-cent tips (my favorite section).
#!/bin/bash
# Determine whether we're in X Windows and call the proper editor
#
if [ "$WINDOWID" = "" ]; then
fte $1 $2 $3 $4 $5
else
xfte $1 $2 $3 $4 $5
fi
GeeCee, Gary Chambers
______________________________________________________________________________________
[IMAGE]
TIP FOR YOUR WEB PAGE
Date: Fri, 3 Jan 1997 17:26:14 -0500 (EST)
From: Ben Boule, bouleb@rpi.edu
One cool tip that I have found useful is the following. If you are running your web page
on your own machine or have the directory on NFS, put the following in your .profile :
cp ~/.netscape/bookmarks.html ~/public_html/bookmarks.html
cp ~/lynx_bookmarks.html ~/public_html/bookmarks2.html
Change for different browsers and server setups.
Then you can link them on your web page, and they get updated every time you log in, start
a new xterm, etc...
Of course, this assumes you don't care about other people looking at your bookmarks.
Later,
Ben Boule
______________________________________________________________________________________
[IMAGE]
RE: TITLEBAR TIP
Date: Mon, 20 Jan 1997 18:40:38 +0200 (SAT)
From: Christopher Gordon, chris@bayes.agric.za
Roger Booth sent in a corrected version of the Titlebar script. I found that in order to
get this working on a Slackware distribution of Linux, using the bash shell, further
modifications were neccesary. The control characters need one \ as opposed to \\. The
"echo" command required an -e switch. The "if" statement only needed one [] not two.
Finally, the script needed to check if "bash" was running or not. I also added a command
to simplify the prompt. Here is the corrected script. It can be run using the source
command.
if [ ${SHELL##/*/} = "bash" ] ; then
if [ $TERM = x"term" ] ; then
HOSTNAME=`uname -n`
label () { echo -e "\033]2;$*\007\c"; }
alias stripe='label $LOGNAME on $HOSTNAME - ${PWD#$HOME/}'
cds () { "cd" $*; eval stripe; }
alias cd=cds
eval stripe
export PS1='\$ '
fi
fi
Standard disclaimers apply.
Regards,
Christopher Gordon,
Remote Sensing, Inst. for Soil, Climate and Water
Pretoria, South Africa
______________________________________________________________________________________
[IMAGE]
TWO BIT TIP -- HEARTBEAT
Date: Wed, 22 Jan 1997 22:29:06 -0800 (PST)
From: Kragen Sittler, kragen@netcom.com
#!/bin/sh # This is a shell archive (produced by GNU sharutils 4.1). # To extract the files
from this archive, save it to some FILE, remove # everything before the `!/bin/sh' line
above, then type `sh FILE'. # # Made on 1997-01-22 22:11 PST by . # Source directory was
`/usr/local/heartbeat'. # # Existing files will *not* be overwritten unless `-c' is
specified. # # This shar contains: # length mode name # ------ ----------
------------------------------------------ # 2222 -rw-r--r-- README # 102 -rw-r--r-- crontab
# 371 -rwxr-xr-x heartbeat # 142 -r-xr-xr-x rc.heartbeat # 1045 -rwxr-xr-x update.sessionid #
touch -am 1231235999 $$.touch >/dev/null 2>&1 if test ! -f 1231235999 && test -f $$.touch;
then shar_touch=touch else shar_touch=: echo echo 'WARNING: not restoring timestamps.
Consider getting and' echo "installing GNU \`touch', distributed in GNU File Utilities..."
echo fi rm -f 1231235999 $$.touch # # ============= README ============== if test -f 'README'
&& test X"$1" != X"-c"; then echo 'x - skipping README (file already exists)' else echo 'x -
extracting README (text)' sed 's/^X//' 'README' && Heartbeat package X My computer seems to
crash often -- about once every ten days. I've been wanting to know when this happens, but
since the computer is busily crashing, it doesn't have time to tell me. (I suspect this
happens because of power outages.) X So I wrote a simple heartbeat package, which would keep
a record in the filesystem when it was alive. That way, I could look at this record when the
machine crashed and tell when and how long it had crashed. X So I wrote a few scripts and
created a new user. I named the heartbeat user 'heartbeat'. (I know it's not really kosher to
have a nine-letter username, but the only thing that has problems with it so far is ls.) X
heartbeat is the first script; it updates a file in /var/log/heartbeat. X Here's the meat of
heartbeat. X X #!/bin/sh X touch /var/log/heartbeat/"`cat /var/run/heartbeat.sid`" X
/var/log/heartbeat should be writable and executable by the heartbeat user; you may want to
use root. heartbeat gets run once a minute on my system, from the heartbeat's crontab: X * *
* * * /usr/local/heartbeat/heartbeat X (For some reason, my crond does not like whitespace
before crontab entries.) X The name of the file it updates is taken from
/var/run/heartbeat.sid. (I'm not sure /var/run is really an appropriate place to put this,
but I couldn't find a better place.) This file should be readable and writable by the
heartbeat user. X heartbeat.sid is updated at boot time by a Perl script called
update.sessionid. update.sessionid also puts some information in the file that heartbeat
updates. X I run update.sessionid (as the heartbeat user) from /etc/rc.d/rc.M, just before
cron is started. X Here's the section from my rc.M: X X.... # # Update heartbeat sessionid. #
This helps us find out when there was a crash. [ -x /etc/rc.d/rc.heartbeat ] &&
/etc/rc.d/rc.heartbeat X # Start crond (Dillon's crond): X.... X and here's
/etc/rc.d/rc.heartbeat: X #!/bin/sh # Update the heartbeat sessionid. # This should be done
before starting cron. su heartbeat -c /usr/local/heartbeat/update.sessionid X Now, when I
want to know when the machine crashed, I can look in /var/log/heartbeat for the times of
system shutdowns -- planned or otherwise. SHAR_EOF $shar_touch -am 0122221197 'README' &&
chmod 0644 'README' || echo 'restore of README failed' shar_count="`wc -c 'crontab' && # MIN
HOUR DAY MONTH DAYOFWEEK COMMAND * * * * * /usr/local/heartbeat/heartbeat SHAR_EOF
$shar_touch -am 0122221197 'crontab' && chmod 0644 'crontab' || echo 'restore of crontab
failed' shar_count="`wc -c 'heartbeat' && #!/bin/sh # script to continually update a file's
timestamp, except when the machine # is down # # This should be put in a crontab to be run
every minute, or five minutes, # or whatever. # # /var/run/heartbeat.sid contains a sessionid
that is incremented at each # bootup, and is suitable for use as a filename. X touch
/var/log/heartbeat/"`cat /var/run/heartbeat.sid`" SHAR_EOF $shar_touch -am 0122210097
'heartbeat' && chmod 0755 'heartbeat' || echo 'restore of heartbeat failed' shar_count="`wc
-c 'rc.heartbeat' && #!/bin/sh # Update the heartbeat sessionid. # This should be done before
starting cron. su heartbeat -c /usr/local/heartbeat/update.sessionid SHAR_EOF $shar_touch -am
0122221197 'rc.heartbeat' && chmod 0555 'rc.heartbeat' || echo 'restore of rc.heartbeat
failed' shar_count="`wc -c 'update.sessionid' && #!/usr/bin/perl # Update sessionid for
heartbeat, creating new sessionid file. # This should be run at boot time. X my
$sessionidfile = "/var/run/heartbeat.sid"; my $heartbeatdir = "/var/log/heartbeat"; X open
SESSIONIDFILE, $sessionidfile or X die "Couldn't open for read"; X my $sessionid = ; close
SESSIONIDFILE; chomp $sessionid; X if ($sessionid !~ /^[a-zA-Z]*[0-9]{4,}$/) { $sessionid =
"boot0000"; } X $sessionid ++; X open SESSIONIDFILE, ">$sessionidfile" or X die "Couldn't
open for write"; X print SESSIONIDFILE "$sessionid\n"; close SESSIONIDFILE; X my
$heartbeatfile = "$heartbeatdir/$sessionid"; X open HEARTBEATFILE, ">$heartbeatfile" or X die
"Couldn't open for write"; X my $message = failed after open; fs full? stopped"; X close
HEARTBEATFILE; X Xexit 0; SHAR_EOF $shar_touch -am 0122211997 'update.sessionid' && chmod
0755 'update.sessionid' || echo 'restore of update.sessionid failed' shar_count="`wc -c
______________________________________________________________________________________
[IMAGE]
2 CENT TIP FOR XDM
Date: Sun, 5 Jan 1997 21:28:02 -0600 (CST)
From: Andrew Dyer, adyer@Mcs.Net
here are several ways you can dress up an xdm login screen:
1. use the 'Xbanner' program available on sunsite
2. run a program like xearth or xfishtank that writes to the X login screen background
3. use a static image display program like 'xv' to put up a simple bitmap
I use xv to put up an image - to do this add a line like the following to the file
/usr/X11R6/lib/X11/xdm/Xsetup_0 (at least that's where is is in my system (Caldera)):
/usr/X11R6/bin/xv -rmode 1 -nc 64 -quit /home/adyer/pics/arcade.bmp
This line will run 'xv' to put the image file at the end of the command line onto the
background window in 'root tiled' mode, dithers the image to only use 64 colors (to
preserve colormap slots on my 256 color display), and tells xv to exit after doing this.
Note that if you run a program like xearth it will continue to run after you have started
the session and will contiinue to run by default until the session is exited. See the
'xdm' man page for more details.
!!!!!!!!!!!!! !! WARNING !! !!!!!!!!!!!!!
programs run by xdm are usually run as root, and so pose a potential security risk if they
are not specifically designed for this. You have been warned :-)
Andrew M. Dyer
______________________________________________________________________________________
[IMAGE]
TWO 2 CENT TIPS -- SYSLOG & X COLOR DEPTH
Date: 13 Jan 1997 10:33:29 +0100
From: Marco Melgazzi, marco@techie.com
Dear sirs
Here's two 2c tips for your wonderful Linux Gazette. Note that all the lines ending with \
have to be joined on one line.
1. :::: Syslog fun (oh no, not again) :::::
Everybody seem to like to put a line like the following in their syslog:
*.* /dev/ttyx
this way every message is printed on an unused tty and the curious ( or worried ) user can
switch to it and see what's going on. This approach has a big advantage ( it doesn't use
any system resource ) and a couple of disadvantages ( notably you have to switch to text
mode to read the messages and then you don't have scrollback ). So I have this little
workaround: in /etc/syslog.conf put something like
*.* /var/adm/current_session_log
In rc.local or whatever file is called before starting syslog
/bin/cat /dev/null > /var/adm/current_session_log
In fvwm you can add something like this:
Style "tail" NoTitle, NoHandles, Sticky, WindowListSkip
Style "tail" StaysOnTop, CirculateSkip
*GoodStuff S-Log telnet-sm.xpm Exec "rxvt" \
rxvt -geometry 132x45-0+0 -sl 1200 -font fixed \
-e tail -n 1200 -f /var/adm/current_session_log &
So when you press the goodstuff button named 'S-log' you get a big rxvt with a nice
scrollback buffer that displays exactly what's going on in the system. If your linux
system stays up for weeks at a time you'll probably have to set up a CRON entry that trims
this file every once in a while but this is left as an exercise for the reader ;-)
To pop down the rxvt a simple Ctrl-C is more than enough. By the way, this approach will
surely save a lot of stress to the monitor electronics: in fact switching from text mode
to hires a) takes time b) involves quite a lot of non-trivial adjustments in the monitor
circuitry so it could likely acceelerate its ageing process.
2. ::::: How to use X with more than one color depth ::::::
I normally use X in 8bit ( since my board is not VRAM based 1152x864 at 70Hz slows down
things considerably ) but, since when I hacked my XF86_S3 to let me use higher clocks in
16bit mode :), occasionally I need to switch to the 16bits depth (notably when using the
oh-so-amazing 'The Gimp').
Since leaving two servers up and running all the time via xdm seemed a waste of memory, by
tinkering with manual pages and articles from the net I came up with a viable alternative.
Let me first tell you one thing: in this way, when the second server is running, you get
both :0 (in 8bit) that is managed by xdm and :1 that has been started on-demand. Since I
don't usually use :1 while I'm online I didn't took the time to provide MIT-MAGIC-COOKIE
authorization for it: this is a thing you -should- do if you plan to use this on the net.
Here there are a couple of my scripts:
::: ----------------------------------------------------------------
:::/usr/local/bin/1open16
::: ----------------------------------------------------------------
xinit ~/.x_rc_for_1_16 -- /usr/X11/bin/X16 :1 vt8 &
::: ----------------------------------------------------------------
:::/usr/X11/bin/X16
::: ----------------------------------------------------------------
#!/bin/sh
exec XF86_S3.new -bpp 16 ${@+"$@"}
::: ----------------------------------------------------------------
:::~/.x_rc_for_1_16
::: ----------------------------------------------------------------
#!/bin/sh
# $XConsortium: xinitrc.cpp,v 1.4 91/08/22 11:41:34 rws Exp $
userresources=$HOME/.Xresources_for_1_16
usermodmap=$HOME/.Xmodmap
sysresources=/usr/X11R6/lib/X11/xinit/.Xresources
sysmodmap=/usr/X11R6/lib/X11/xinit/.Xmodmap
export PATH= .... path ....
# merge in defaults and keymaps
if [ -f $sysresources ]; then
xrdb -merge -display :1 $sysresources &
fi
if [ -f $sysmodmap ]; then
xmodmap -display :1 $sysmodmap &
fi
if [ -f $userresources ]; then
xrdb -merge -display :1 $userresources &
fi
if [ -f $usermodmap ]; then
xmodmap -display :1 $usermodmap &
fi
....
misc other variables
....
exec fvwm -f .fvwmrc_for_1_16
::: ----------------------------------------------------------------
::: in ~/.fvwmrc_for_1_16 I have this: I'm not sure this duplication
::: is necessary but in my configuration it is. YMMV
::: ----------------------------------------------------------------
Function "InitFunction"
Exec "I" xrdb -display :1 -merge ~/.Xresources &
Exec "I" xmodmap -display :1 ~/.Xmodmap &
Module "I" GoodStuff
Exec "I" emacs &
EndFunction
In this way when you execute the 1open16 script you will get a 16bit screen on :1 at the
default resolution you put in your system XF86Config for 16bit depth.
Things get a little more hairy if you want to open the new screen with a different set of
resolutions: unluckily ( I guess for security reasons ) XFree lets you use a new
XF86Config -only- if you are root. So to play Quake on :1 you have to do the following...
::: ----------------------------------------------------------------
::: in ~/.fvwmrc ( this is nice for password requests, I use it all the
::: time, just put the word 'Password' in the rxvt that you need and use
::: the supplied style. I use it for going online, to access netscape &
::: other net stuff ( I'm paranoid so I created a user named -net- that
::: I use for all internet related stuff, I hate live-data trojans etc.)
::: you get the point.)
::: ----------------------------------------------------------------
Style "*Password" NoTitle, NoHandles, Sticky, WindowListSkip,StaysOnTop
::: in a menu entry
Exec "Quake (normal)" exec rxvt -fn \
"-b&h-lucidatypewriter-medium-r-*-*-*-180-75-75-*-*-*-*" \
-geometry 40x1+1-1 -T \"Quake Password" -e \
su root -c "/home/marco/bin/qk" &
::: ----------------------------------------------------------------
::: /home/marco/bin/qk. The redundant su is needed if you plan to launch
::: this file from the command line too.
::: ----------------------------------------------------------------
cd /home/marco/quake
su -c "xinit ./xf86quake -- /usr/X11/bin/X -bpp 8 :1 vt8 -xf86config \
/home/marco/lib/XF86Config.quake"
Of course /home/marco/lib/XF86Config.quake will contain only the resolution that I usually
play quake at ( that is 400x300 or 512x384 ). In this way you can play quake without
hassless even if you usually run at 1000-or-so x 800-or-so at whatever depth. Now if only
Linus released the updated 1.06 xf86quake ;-) (in 1.01 you can't use a custom heap, you
have the fixed 8mb one :( ).
Hope you'll like these tips!
Marco Melgazzi
______________________________________________________________________________________
[IMAGE]
X WINDOWS COLOR DEPTH
Date: Fri, 17 Jan 1997 08:38:20 -0500 (EST)
From: Aaron B. Dossett, aarond@ewl.uky.edu
>I have recently been messing with my x-server, and have managed >to get a depth of 16, ie
2^16 colors. This works >really nice with Netscape, but some programs (doom, abuse, and
>other games) wont work with this many colors. Do >you know of a fix? I have tried to get X
to support multiple >depths--to no avail. The man-page suggests that some >video cards
support multiple depths and some don't. How do I know >if mine does.
Well, if your video card has enough RAM and you've got enough modes defined in your
XF86Config file then you can specify the bit depth from the command line. If you have a
link called X to the server then the command
X -bpp 8 or X -bpp 16 or X -bpp 24
can be used. I like to alias the commands X8, X16, and X24 to the above. For this to work
best you should have your XF86Config file setup so that each mode uses the maximum
resolution possible.
Aaron Dossett, aarond@ewl.uky.edu
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
______________________________________________________________________________________
This page maintained by the Editor of Linux Gazette, gazette@ssc.com
Copyright &copy; 1997 Specialized Systems Consultants, Inc.
[IMAGE]
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
News Bytes
CONTENTS:
* News in General
* Software Announcements
[IMAGE]
______________________________________________________________________________________
NEWS IN GENERAL
______________________________________________________________________________________
LINUX GAZETTE ITALIAN EDITION
Date: Fri, 10 Jan 1997 14:42:52 +0100
The first issue of the Italian Edition of the Linux Gazette, is now available on our site,
www.media.it/LUGBari/lgtp/index.html. It is in the spirit of helping italian Linux users
and, naturally, this italian edition is under the copying license of your original Linux
Gazette.
Bye (and many many thanks!)
Francesco De Carlo, fdecarlo@sole.media.it
CICCIO-X, LUGBari Coordinator
______________________________________________________________________________________
LINUX ADVOCACY MINI-HOWTO
Date: Sat, 11 Jan 1997 11:53:19 +0100 (MET)
This is the Linux Advocacy HOWTO and is intended to provide guidelines and ideas to assist
with your Linux advocacy efforts. -- authored by Paul L. Rogers, Paul.L.Rogers@li.org
Related Links:
Lars Wirzenius also has some thoughts about Linux advocacy.
The Linux Advocacy Project's goal is to encourage commercial application developers to
provide native Linux versions of their software.
______________________________________________________________________________________
LINUX IN THE NEWS
Linux was chosen by PC Week as part of its list for the top ten products of 1996. See the
December 16, 1996 issue. The same issue has a related article about Linux and the Internet.
______________________________________________________________________________________
LINUX SITES TO CHECK OUT
http://www.m-tech.ab.ca/linux-biz
This site contains anecdotal references about the commercial applications of Linux. Example
uses of Linux in various industries, fulfulling various tasks are listed. Includes form /
CGI script that visitors can use to enter data about their own commercial Linux sites.
-- Idan Shoham, idan@m-tech.ab.ca
http://www.xnet.com/~blatura/linapps.shtml
The Linux Applications and Utilities List is an organized collection of pointers to the WWW
home pages of over 600 different Linux compatible application programs, system admin tools,
utilities, device drivers, games, servers, programming tools, file, disk and desktop
managers, internet apps, and more. The January 8 edition has added links to over 80 new
programs, as well as corrections to numerous existing listings. -- Bill Latura,
blatura@xnet.com
http://www.linuxware.com
This site is a Linux Support, Information, and general purpose Linuxer Hangout Site -- a
meeting place for people interested in learning more about Linux, providing help to other
Linuxers, and promoting Linux!!! -- Peter Lazecky, peter@linuxware.com
______________________________________________________________________________________
PNG ARTICLE (SEE ISSUE13) UPDATE
Apparently Netscape has finally committed to supporting PNG in Navigator and actually made
public statements to that effect at its Internet Developers' Conference last October,
although there's no indication of it anywhere on their web site. The only question is when:
Navigator 4.0 has a fixed release date, and PNG support may not be ready by then.
-- Greg Roelofs, newt@pobox.com
______________________________________________________________________________________
ROCHESTER, REVISED OS SEMINAR SERIES SCHEDULE
Date: Sun, 12 Jan 1997 02:36:18 GMT
Computer Science House at Rochester Institute of Technology Presents: an Operating System
Seminar Series Wednesday evenings at 8:00PM. Attendance is free of charge and is open to
the public.
* February 5: The Inferno Operating System for Everything From Embedded Systems To
Network Operating Systems. - David Bort (Student, RIT)
* February 12: Sun Microsystems new JAVA Based Network Computers - Jeff Rice (Sun
Microsystems)
* February 19: ShagOS -- An experimental Object Oriented Micro kernel. - Frank Barrus
(Xerox)
* February 26: Solaris - Geordie Klueber (Sun Microsystems)
For additional information, directions, comments or if you would like to be a guest
speaker, e-mail tad@csh.rit.edu.
Computer Science House, cshouse@csh.rit.edu,
http://www.csh.rit.edu/os-seminars
______________________________________________________________________________________
LINUX CD GIVEAWAY LIST
Date: Mon, 13 Jan 1997 05:16:52 GMT
If you have a spare Linux CD to give away, you can list your email address at
http://emile.math.ucsb.edu:8000/giveaway.html
Interested parties will contact you, then send in a self-adressed stamped envelope and you
send them the CD.
If you would rather (or in addition) lend a Linux CD locally, you can now specify that as
well.
For additional information:
Axel Boldt, boldt@math.ucsb.edu, http://www.math.ucsb.edu/%7Eboldt/
Univ of California at Santa Barbara, Dept of Mathematics
______________________________________________________________________________________
LINUX BROWSER PROJECT - A NEW WWW BROWSER FOR LINUX
Date: Tue, 14 Jan 1997 06:34:56 GMT
Announcing the Linux Browser Project -- a group of developers developing a world wide web
browser for Linux and other platforms. The goal of this project is to develop a web browser
which consists of a modular program architecture based around a small, fast kernel which
would load necessary modules on demand.
The project is in its early stages, and we are announcing the project at the moment to make
ourselves known to the rest of the Linux community. If anyone would be interested in
helping us out in any way, please feel free to join the mailing lists or visit the web site
and let us know that you are willing to help. For additional information:
See the Linux Browser Project home page at http://www.tjhsst.edu/LBP/.
Jason A. Miller, Project Coordinator, jasonm@trib.com,
The Linux Browser Project Team
[IMAGE]
______________________________________________________________________________________
SOFTWARE ANNOUNCEMENTS
______________________________________________________________________________________
XFMAIL 1.0 - MAIL PROGRAM FOR X
Date: Sun, 05 Jan 1997 00:59:12 GMT
Xfmail 1.0 is finally out! XFMail is an X-Windows application for sending and receiving
electronic mail. It uses the XForms GUI library toolkit by T.C. Zhao and Mark Overmars.
It has a user-friendly interface and online help to make it easy to use. It implements most
of the mail functionality in one program and it does not require any additional tools.
You can ftp XFMail at:
ftp://ftp.x.org/contrib/applications/xfmail-1.0.tar.gz
ftp://Burka.NetVision.net.il/pub/xfmail/xfmail-1.0.tar.gz
For additional information:
http://Burka.NetVision.net.il/xfmail/xfmail.html
Jacek Bochenek, jacek@coig.katowice.pl
Organization: COIG S.A.
______________________________________________________________________________________
IMAGEMAGICK 3.7.9 ELF BINARIES - GENERAL IMAGE MANIPULATION TOOL
Date: Sun, 05 Jan 1997 00:59:19 GMT
ImageMagick (TM), version 3.7.9, is a package for display and interactive manipulation of
images for the X Window System.
ImageMagick supports also the Drag-and-Drop protocol form the OffiX package and many of the
more popular image formats including JPEG, MPEG, PNG, TIFF, Photo CD, etc.
You will also need the package libIMPlugIn-1.0-elf to get it working. Here are the
locations you can get the packages from:
Site: sunsite.unc.edu /pub/Linux/X11/xapps/graphics 942k ImageMagick-3.7.9-elf.tgz 1k
ImageMagick-3.7.9-elf.lsm 886k libIMPlugIn-1.0-elf.tgz 1k libIMPlugIn-1.0-elf.lsm
For additional information:
Alexander Zimmermann, Alexander.Zimmermann@FMI.Uni-Passau.de,
http://www.uni-passau.de/~zimmerma
Organization: Universit<69>t Passau
______________________________________________________________________________________
VISUAL TCL 1.07 BETA
Date: Sat, 11 Jan 1997 02:42:27 GMT
Visual Tcl 1.07b is a quality application development environment for UNIX, Windows and
Macintosh platforms. Visual Tcl is written entirely in Tcl/Tk and covered by the GNU
General Public License.
Please choose the location nearest you since my connection can become saturated at peak
times.
Home Site: http://www.neuron.com/stewart/vtcl/ Australia:
http://holmes.ccs.deakin.edu.au/vtcl/ United Kingdom: http://www.jessikat.demon.co.uk/vtcl/
Germany: http://www.ifconnection.de/~rjs/vtcl/ US East:
http://www.ultra.net/~eugene/mirror/vtcl/ US Mid: http://chaos.uark.edu/vtcl/
For additional information:
Stewart Allen, stewart@neuron.com
______________________________________________________________________________________
NEXS 1.3-BETA X-WINDOWS SPREADSHEET NOW AVAILABLE
Date: Mon, 13 Jan 1997 05:16:23 GMT
X Engineering Software Systems (XESS Corp.) announces the immediate availability of the
BETA version of the NExS 1.3 spreadsheet for Linux and UNIX workstations.
NExS, the Network Extensible Spreadsheet, is a full-featured, graphical spreadsheet
developed specifically for UNIX and the X Window System. NExS has more than 237 built-in
business and scientific functions, allows user-customized functions, displays data using 2
and 3 dimensional graphs, and imports and exports data in a wide variety of formats
(including HTML tables).
Demonstration copies and additional conNExions plug-ins may be downloaded from
http://www.xess.com. NExS is priced at $149 for the Personal Edition, and $249 if a
floating license is desired. For addtional information:
xess@vnet.net
Vnet Internet Access, Inc. - Charlotte, NC.
______________________________________________________________________________________
PHT RELEASES RED HAT 4.0
Date: Tue, 14 Jan 1997 06:35:52 GMT
Pacific HiTech is proud to announce the release of our newest Linux product for the i386
architecture:
Turbo Linux: Red Hat 4.0
It features a modular 2.0.18 kernel, better networking, more packages, and, of course, the
floppy-less install. The second CD contains the entire contrib/ directory from
ftp.redhat.com (the Live Filesystem was scrapped in order to put the contrib/ directory on,
which we felt would be more useful for more people).
The 2 CD set is only $19.95 plus s/h. If you want more details on the product, visit
http://www.pht.com/linux.
For additional information:
Scott M. Stone, sstone@pht.com
Chief Linux Developer/UNIX SysAdmin for Pacific HiTech, Inc. http://www.pht.com/
______________________________________________________________________________________
PHT RELEASES MKLINUX DR2
Date: Tue, 14 Jan 1997 06:35:56 GMT
Pacific HiTech is proud to announce our newest Linux offering for the PPC architecture:
MkLinux DR2 is the latest pre-release version of MkLinux, and it is MUCH MUCH better than
DR1 - more stable, more hardware support, and a much smoother installation. It was
uncompressed from the FTP distribution and burned as a Macintosh HFS format CD - you don't
need to decompress the files onto your hard drive, you can just put in the CD and GO.
It's only $19.95 plus s/h. See http://www.pht.com for ordering information, or email
sales@pht.com.
For additional information:
Scott M. Stone, sstone@pht.com
Chief Linux Developer/UNIX SysAdmin for Pacific HiTech, Inc. http://www.pht.com/
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
______________________________________________________________________________________
This page written and maintained by the Editor of Linux Gazette, gazette@ssc.com
Copyright &copy; 1997 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
THE ANSWER GUY
By James T. Dennis, jimd@starshine.org
______________________________________________________________________________________
CONTENTS:
* Netscape Mail Block
* Dealing with e-mail on a pop3 server
* Security Problem
* More on Security Problem
* Dial-up Problem
* X Window Problem
______________________________________________________________________________________
NETSCAPE MAIL BLOCK
Date: Sun, 15 Dec 1996 23:16:10 -0800 (PST)
hi... mitch here in mobile, alabama...
i need to refuse to accept email from a particular person... how can i configure netscape
and/or cnd1.0 to bounce the person's mail back to them?
I'd use procmail. CND uses procmail as your "local delivery agent" (by default). This means
that sendmail passes any mail to a local account to procmail and lets procmail due the
final delivery to your mail box (/var/spool/mail/$YOUR_LOGIN_NAME).
However, when procmail does this, it checks for a .procmailrc file in your home directory
(and does some ownership and permissions checks on it for you).
procmail is a little programming language specifically for processing mail.
Your .procmailrc file can have a variety of settings and clauses (which are called
"recipes" by the author). You can also modularize this by using a variety of INCLUDE
directives. Here's a simple example that should get you started.
:0 hr
* ^From.*spammer.you.despise@spamhaven.com
* !^FROM_MAILER
* !^FROM_DAEMON
* !^X-Loop: ${USERNAME}@`hostname`"
| (formail -r -A"X-Loop: ${USERNAME}@`hostname`" \
-A"Precedence: junk" ;\
echo "Your mail is not welcome here."
echo "Please don't mail me again."
echo
cat ~/your.signature.or.flame
)
The :0 marks this as a new recipe (so each new recipe starts with a :0 line). The 'h' on
that line is one of several flags to procmail about what parts of the message to hand to
your action line (which comes up later). 'h' says: give me the header 'r' says: treat the
incoming data as "raw" (so his failure to put a blank line at the end of his message won't
cause your response to fail).
The four "star" lines after that are conditions -- the first specifies that the header
indicates that the message be "from" your spammer (or unwanted sender). This will actually
match any "from" or "From:" line that contains your targets e-mail address. The next two
lines try to ensure that you don't respond to daemons and mailers (mailing lists). The next
one (which you should fill in with your username and hostname) makes sure that your don't
respond to your own response.
Those three conditions are to protect your script from being tricked into doing bad things.
Consider them to be the minimum overhead on any autoresponders that you write.
The next line (starting with a "|" pipe character) is the action to take.
In procmail there are three types of actions. A filename simply specifies an mbox (elm,
pine, or mailx compatible) folder to file this away in. A directory name specifies an mh or
mmdf folder to store the message in (mh and mmdf use different naming schemes for the
messages in their folder directories -- you don't need to worry about this unless you use
on of these mail user agents). A '!' (bang) line specifies an e-mail address to which to
bounce the message. A '|' (pipe) line specifies that the message should be filtered through
a local program.
formail is a program that comes with the procmail package. It "formats mail headers." This
particular formail command formats a "reply" (-r) header and adds two additional header
lines -- a standard "Precedence: junk" line and a personal "X-" line (which the RFC822 spec
allows you to use to embed custom information into a header). This is where your message
adds the line that would prevent an attack by routing your response back into your script
(a mail loop).
The echo and cat statements after the formail line just provide output that is appended
after the mail header. This becomes the body of your response. You can add additional echo
lines -- or you can create a file and just 'cat' it here.
If you are new to procmail (which is almost certain given your question -- autoresponders
are some of the first things procmail'ers learn) you may be nervous about 'breaking'
something and losing some of your mail. So -- to protect yourself from that you might want
start your .procmailrc with the following simple recipe:
:0 c
fallback
Which (if it is the *first* recipe) simply appends a copy of every incoming message to a
file (in your ~/Mail directory by default) named fallback. You can compare the contents of
that folder to your inbox until you're confident that things are working as you expect.
Please read the procmail and procmailex (examples) man pages for more details. The author
Stephen van der Berg, has also written an automated mail list management package called
SmartList -- which is highly regarded among people who've tried it. I like SmartList *much*
more than majordomo.
--Jim
______________________________________________________________________________________
DEALING WITH E-MAIL ON A POP3 SERVER
Date: Tue, 28 Jan 1997 04:02:06 -0800 (PST)
From Moe Green:
Is there any way (or any program out there) which will not only get my email from a pop3
server off of one account, then distribute it to multiple users on my system by either the
from: or subject: lines???
Example: Perhaps popclient could get the mail and save to temp, then is there a program
which would go through and say, hmmm...this mail is from johndoe@linux.org and it goes to
root...then the next message is from mike@canoe.net and it goes to dave???
Thanks for your time, keep up the good work.
-Moe Green, starved@ix.netcom.com
It is possible to write procmail scripts that can do this sort of thing. However I don't
recommend this approach at all.
The current version of 'popclient' is called 'fetchmail' (because it supports IMAP and some
other mail store and forward protocols).
It's default is to fetch the mail from your POP or IMAP server and feed it to the smtpd
(sendmail) on your local host. This means that any special processing that would be done by
the aliases or .forward files (especially any processing through procmail scripts) will be
done automatically.
It is possible to over-ride that feature and feed the messages through a pipe or into a
file. It is also possible, using procmail or any scripting language, to parse and dispatch
the file. Using anything other than procmail would require that you know *alot* about
RFC822 (the standard for internet mail headers) and about e-mail in general.
I did write an article on procmail this month -- but may have submitted it too late for
inclusion into this month's Linux Gazette. The gist of it is available on my own mail
server (send mail to info@starshine.org with a subject of ``procmail'' or ``mailbot'').
The reason I don't recommend all of this is that it violates the intentions and design of
internet e-mail. A better solution is to find a provider of UUCP services (or at least
SMTP/MX services). UUCP is the *right* way to provide e-mail to disconnected (dial-up)
hosts and networks. It was designed and implemented over 25 years ago and all of the mail
systems on the Internet know how to gateway to UUCP sites.
As for SMTP/MX services for disconnected hosts/networks. Various ways of hacking sendmail
and DNS configurations have been developed in the last few years -- with a variety of shell
scripts and custom programs to support them. All of these provide essentially the same
services as mail via UUCP over TCP -- but without conforming to any standard (meaning that
whatever you learn and configure with one ISP probably won't work with the next one).
Glad I could help. I hope that article on procmail helps.
--Jim
______________________________________________________________________________________
SECURITY PROBLEM
Date: Tue, 28 Jan 1997 04:02:06 -0800 (PST)
From Jay:
Recently a cracker got into my linux system on the internet. He didn't do a lot of damage
but he did turn off system logging. I guess so I couldn't see what he'd done. Now I can't
get it working again....
1. I've made sure that the syslogd program is running using 'ps'
2. I've read the syslogd.conf file to make sure it's logging everything, and where it's
going to.
3. I've checked permissions on the log file
4. I did a 'kill -HUP' on the syslogd process and it writes 'restart' to the log
5. 'logger' does nothing when I run it (no log entry, no error)
6. All my C programs that wrote to syslog don't anymore
Anyone have any good ideas what to do from here?
Thanks
--Jay, jay@shadow.ashpool.com
I do but they are rather too involved for me to type up tonight.
I really recommend that you reinstall the OS and all binaries from scratch whenever you
think that root has been compromised on a system. I realize that this is a time-consuming
proposition -- but it is the only way to really be sure.
I also recommend tripwire (ftp.cs.perdue.edu in the COAST archive -- and it's mirrors).
Please feel free to write me if you continue to have system security problems.
jimd@starshine.org
Sorry to take so long to respond. I've been literally swamped all month.
--Jim
______________________________________________________________________________________
MORE ON SECURITY PROBLEM
Date: Tue, 28 Jan 1997 18:56:22 -0800 (PST)
From Jay:
>>> Recently a cracker got into my linux system on the internet.
>>
>> Did you restart the whole system?
>> I would consider replacing syslog from your CD's and
>> restarting your system.
>
I found that the cracker had replaced my syslogd with a packet sniffer. I think he had
copied the syslogd code and replaced parts of it with his sniffer. It seemed to have some
functionality but not a lot...
I also found a SUID version of bash in my /tmp directory. My thought is that this is how
he originally got root access.
Not too surprising. He was probably using a 'rootkit.' However he obviously didn't do a
very good job of covering his tracks.
You should consider all passwords for all of the systems on the local net to be
compromised. Force password changes across the board and consider installing ssh or stelnet
(secure, encrypted replacements to rlogin/rsh and telnet respectively).
He probably got in through the "Leshka" sendmail bug (allowing any shell user to create a
root owned SUID shell in /tmp/ on any system with an SUID root copy of sendmail (version
~8.6.x to 8.7.x ???) using a bug in sendmail's handling of ARGV[0] and it's subsequent
SIGHUP handling.
Everyone using earlier versions of sendmail should upgrade to 8.8.3 or later
(www.sendmail.org for details).
How important are this system and the other systems on the same LAN segment to your
business?
I'd seriously consider hiring a qualified consultant for a full day risk assessment and
audit. Unfortunately you'll probably pay at least $125/hr for anyone that's worth talking
to and many of the "security consultants" out there are snake oil salesmen.
I personally trust Peter Shipley (www.dis.org) and Brent Chapman (www.greatcircle.com)
(co-author of the O'Reilly Firewalls book) Strat Rose (www.virtual.net) and Dan Farmer
(www.trouble.org) (co-author of SATAN). Most of them are live in the SF Bay Area (silicon
valley) and most of them aren't available most of the time (Brent is working on a large
project to integrate the SGI and Cray WAN's; Strata has accepted a full-time position at
synopsis.com, etc).
I only consider myself to be a student, at best an apprentice, at data security. I'm
willing to help -- but I can offer a list of satisfied clients for RASA services and I have
no official "credentials."
--Jim
______________________________________________________________________________________
DIAL-UP PROBLEM
Date: Tue, 28 Jan 1997 22:56:35 -0800 (PST)
From Seth Vidal:
I was reading your answer in LG(#13) to the individual who had slow rate problems with
ppp. Something which he did not mention that might be of help is the MTU. Some isp's set
the mtu or have ppp do the negotiation. NOT all. Some of the newer ones have not quite
figured out that a 14.4 or 28.8 is not going to get a packet size over 576 very often. If
he sets his mtu to 576 (or even 296 for a 14.4) he may be able to force the provider's
setting down. I have found that in a standard (slackware or redhat) linux distribution
that the mtu defaults to 1500 which will result in slow downs and problems if your modem
encounters errors frequently. I know what ppp is "supposed to do" when set up correctly.
But he cannot control the ignorance of his ISP and therefore it would be to his behest to
give that a try. If you'd like to pass the information along to the individual who wrote
the message feel free. I hope this helps him and any others.
cheers,
Seth Vidal, skvidal@terminus.ehc.edu
______________________________________________________________________________________
X WINDOW PROBLEM
Date: Tue, 28 Jan 1997 04:02:06 -0800 (PST)
From: Chris Lee, techno@usa.net
1.) X Windows I got a Cirrus 5434 1mb video card, whenin 640x480x8bit the video is *fine*
not great, I get little specs once in awhile on the screen, they go away with a simple
[refresh] but still... When in 800x600x8bit I get lines, not specs anymore, alomst allways
horizontial, and about 3pixels high, and allways croos the entire screen, not the virtual
screen though, and they also go away with a simple [refresh] thses line occur alot more
then the specs did. My vid card works fine in DOS/Windows. Any suggestions ?
You can look for the SuperProbe utility that comes with most recent distributions. This
will provide info that can be autodetected about your video card.
Frankly XWindows configuration under XFree86 is black magic. A few people are really good
at it and mere mortals (such as I) just plug along and hope for the best.
The new XFree86 3.1.2 release seems to be better about this but I'm sure that I'm not
getting the optimal color and clock settings from my various X installations either.
2.)Is there any Linux or X-Windows mailing-lists ? would help alot for me.
There are many Linux mailing lists -- and some of them and some independent ones cover
XFree86 (which is used by Linux, FreeBSD and the rest of the free BSD derivatives (NetBSD
and OpenBSD).
The three best web sites for information about Linux seem to be:
* http://www.li.org/, Linux International
* http://www.ch4549.org/lust/, L.U.S.T. (Linux User's Support Team)
* http://www.ssc.com/linux/, SSC Inc.
I don't know much about X Windows and the XFree86 project but I think they maintain a web
site -- probably at www.xfree86.org.
It's an often overlooked fact that there are competitors to Linux in the field of freely
available Unix for PC's. You can look at www.freebsd.org, www.netbsd.org and
www.openbsd.org for some of those.
Thanks for your time :)
Chris Lee, Computer Science
P.S. You Linux people are great, so much out there, so many people helping you,
nothing like this for DOS/Windows
DOS heralded the "sharing" of software (shareware) while Linux and the GNU project has
promoted a *giving* of software -- and support.
I think one is largely and extension of the other.
Personally some of the best news I've heard for die hard PC users in the last year is the
announcement that Caldera purchased DR-DOS and intends to release the sources as soon as
the clean up the code enough to compile cleanly in a sane production environment. Look at
www.caldera.com for details about that.
OpenDOS will be one of the final pieces in the puzzle of how we (PC users, IS managers, and
others) can truly protect the investment we've made in our legacy software. (Currently,
with dosemu -- the BIOS emulator, you have to install a copy of DOS unto your system in
addition to installing and configuring the Linux interface to your DOS programs -- which is
want dosemu provides).
-- Jim
______________________________________________________________________________________
Copyright &copy; 1997, James T. Dennis
Published in Issue 14 of the Linux Gazette
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
CLUELESS at the Prompt: A New Column for New Users
By Mike List, troll@net-link.net
______________________________________________________________________________________
I'm sure you've heard it before, but Welcome to Linux! You've heard the stories, your
friends told you "Don't do it" but the allure of an operating system with at least the
power of NT that can run on 4 MB of RAM on the same disk, even on the same partition with
your DOS/Windows installation, was too big to be ignored. So you went on a FTP spree or
bought a Red Hat or Slackware CD, installed it and you are confused, things don't work the
way you expected, the man pages seem to be written in another language, and the people on
the USENET keep telling you to RTFM and belittling you.
That's why I decided to ask if I could write this column, it happened to me. Actually, when
I got into computers (less than a year ago,) my friend Trippy told me to learn DOS before
trying Windows. Thanks Trippy, you saved me a lot of trouble. So when I read about Linux, I
thought -WHOA COOL!!, and downloaded the mini-linux distribution from Sunsite."HEY!Wait a
minute, how come the keyboard doesn't work right?" Turns out the key table is Portuguese
and requires file editing to be usable by us Yanks. Thanks to SGK from the Debian group, I
got that squared away, so I decided to go with Debian, but with my small disk and no
CD-ROM, Debian's Compatibility/Conflict Resolution was too much for me. So I got a second
disk, 100 MB but it was still too small. So I decided to give Slackware a try. That's what
I'm running now.
The point is, I'm not a college educated computer expert but I still ended up(for now) with
a running linux box. You can too, if you are willing to tinker (hack later, tinker now).I
made every possible mistake, I thought until I saw some of the questions in the news
groups.
But enough about me, what do you think about me?;-)
The first things you need to know after you install Linux are the most common commands.
Here I'm going to assume that you have at least some DOS background. The following list
will attempt to correlate Linux commands:
LinuxDOS ls /directory/namecd\directory\name -- dir ls /directory | more
ls " " | lessdir | more cat /filetype \file cat " " | more
less /file" " | more cp /file /file /tocopy \file \to cd /directorycd\directory mkdir
/directorymkdir \directory rm /filedel \file
This list is not nearly complete, there are many more commands in both OS but these are
very likely the most commonly used ones. For command help in DOS type: help :in linux type:
man (command, substitute the command name): Both of these help utilities give options or
switches that change the nature of the command. You can see that there are similarities in
the command line operation of both OS, historically they share a common ancestry. In fact,
to use a oversimplified view, at the command line linux could be thought of as SUPERDOS. In
fact this SUPERDOS can actually be used to run MS Windows - check into WINE and WABI home
pages on the Internet.(More on those later, maybe.)
One of the next things you will need to do is find out how to write or change file contents
with an editor.I used to think elvis was the easiest editor, until Konrad Rokicki told me
about pico, which comes with the pine mail server. If you used MS Write or Notepad, you'll
find it very easy to use. Save Emacs for another day unless you are a good typist, I found
the keyboard commands to be confusing for my two-fingered style. If you don't have pico
installed, try elvis in the input mode, by typing: input filename, it's pretty easy too,
except watch out for command mode and input mode (type: man elvis :and read the page.If you
have a CD version of Linux, you either have pico installed or can have it if you choose.
If you're like me one of your priority projects will be to to do is use an Internet
protocol to connect to your Internet Service Provider. My ISP uses PPP so that's what I
used, and the following descriptions are for PPP.
The first thing you will need to confirm is that your kernel supports PPP, either in the
kernel or by loadable modules. Type: pppd :and hit enter. If your kernel doesn't support
PPP, you'll get a negative message, if you get a prompt you can assume for now that it's
supported.
Next you will need to type: ls /usr/sbin | more :and hit enter. Look for files called
ppp-on and ppp-off. Next, type: ls /etc | more : and hit enter. Here you will be looking
for a file called resolv.conf. Then type: ls /etc/ppp : you can skip the: | more :this
time, since it's a small directory,and hit enter. You'll be looking for files called
options and ppp-on-dialer.
Edit your /etc/resolv.conf to look something like:
domain net-link.net
nameserver 205.207.6.2
nameserver 205.217.6.3
gateway 205.217.6.10
Naturally you will have to change the name and numeric to match that of your ISP .
Next, edit your /etc/ppp/options file to look something like this:
/dev/modem
38400 # at this line you could substitute 19200, 57600, 115200
defaultroute
noipdefault
debug
crtscts
lock
modem
These two files are necessary to either of the methods I am going to describe.
Now you can use minicom to dial up your ISP. Type: minicom :, and when it loads, type:
ATDTYOURISPNUMBER :hit enter. When the remote modem answers you will be prompted for your
username and password. When you have responded with this information, a string of garbage
characters will run across the screen. Type: ctrl(key)a :then: Q :which will let you out of
minicom without hanging up the modem. Then immediately type: pppd :then hit enter. Type:
ping YOURISP'SNUMERIC :you will get a message that will inform you if you are connected. If
you get a message that says in part "network not reached" try again. If no luck after a
couple more tries, check to see that the files you edited have the correct information. Try
changing your connection speed in /etc/ppp/options to 19200 and try again. If you connect
this time, then one at a time try the faster speeds until you can't connect, then drop back
to the fastest speed that worked.
There is an easier method using the script /usr/sbin/ppp-on, that involves editing that
file to give your ISPdialup number, username, and password and optionally your connection
speed. It is commented to help you figure out how to change those lines that you need to
change. When that is done correctly, you can dial up by typing: ppp-on : Pretty cool, huh?
If these methods don't work for you, start by reading the PPP_HOWTO in your
/usr/doc/faq/howto directory, then respond by e-mail to troll@net-link.net, telling me any
error messages, and I'll try to square you away.
There is another method using the chat program, but I haven't had much luck there, yet.
Future installments, if any will fill you in on that if it seems that it's wanted.
Personally, ppp-on is just fine for me so far.
you will want to get an e-mail program and a browser, if you don't already. I recommend
lynx. It's fast and you don't need X installed to use it. There probably is a lynx binary
in your distribution, but if not you can get one from sunsite or other ftp.Pine is a good
mail program, and it includes the pico editor, as noted above.
NOTE TO LINUX EXPERTS- I would be glad to accept reasonable criticism of this article and
the information therein. I don't really want to put up with heavy fire, if you can help the
new user better than me, write an article yourself, there are plenty of avenues where such
information would be of great service.
NEXT TIME- E-MAILTROLL@NET-LINK.NET ME AND ASK, OTHERWISE I'LL JUST WRITE ABOUT WHAT GAVE ME
TROUBLE AND HOW I GOT PAST IT.
TTYL, Mike List
______________________________________________________________________________________
Copyright &copy; 1997, Mike List
Published in Issue 14 of the Linux Gazette
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
______________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
The Cracraft and Lijewski DIRED Programs
By Grant B. Gustafson gustafso@math.utah.edu
______________________________________________________________________________________
The directory navigator and program launcher called "DIRED" in the original incarnations of
EMACS has two stand-alone Unix clones. Mike Lijewski's "dired" 2.2 is written in C++
(1996). The original "dired" was written in C by Stuart Cracraft (1980), available as
version 3.05 (1997).
Historically, shortly after emacs "dired" appeared in the TECO implementation, a
stand-alone version was written by Stuart Cracraft (1980). The emacs version and the C
version have not kept up with one another.
Lijewski wrote "dired" in 1990, while at Cornell University Theory Center, without any
knowledge of Cracraft's "dired". The Theory Center ran on IBM VM/CMS, under which there is
a utility call "file manager". This program manages the flat VM/CMS file system and
represents the main user interface into files. The creation of "dired" eased the transition
from VM/CMS to Unix.
Lijewski's "dired" has the advantage of hindsight and C++ program development so it
promises to be written in modern syntax and very maintainable. Cracraft's "dired" was
rewritten in 1996 in ANSI C. It suffers with flaws in both design and readability, but the
features are there.
______________________________________________________________________________________
COMMON FEATURES OF CRACRAFT'S AND LIJEWSKI'S "DIRED"
* Copy current file
* Hard link current file to another file.
* Symbolic link current file to another file.
* Unzip current file (gunzip).
* Zip current file (gzip).
* Rename current file.
* Display help.
* Cursor up one.
* Cursor down one.
* Back one page.
* Forward one page.
* Go to first file.
* Go to last file.
* Do shell command /w filename substitution.
* Search forward for file matching regular expression.
* Search reverse for file matching regular expression.
* Launch EDITOR on a file or DIRED on a directory.
* Recognize new window size and refresh screen.
* Delete current file
* Prompt for and edit a directory.
* Change the mode of the current file.
* Launch PAGER on this file.
* Sort the file list.
* Print file contents.
* Reload directory.
* Abort DIRED.
* Suspend DIRED.
* Exit immediately.
* Setup by command line, resource file or environment variable.
Minor differences exist in the implementation of these features. Cracraft's dired supports
split screen. Lijewski's dired supports scrolling by half-page. Deletes in Cracraft's dired
are done in batch whereas Lijewski's dired does them immediately.
Curiously, the common features of the two direds also account for the most often used dired
commands.
The differences between Lijewski's "dired" and Cracraft's "dired" in 1997 appear below.
Many features commonly exist in both versions, so only the superficial differences are
discussed. Strengths and weaknesses of each are also listed.
______________________________________________________________________________________
UNIQUE FEATURES OF LIJEWSKI'S "DIRED"
* Compress current file.
* Uncompress current file.
* Change the group of the current file.
* View only files matching a regular expression.
Strengths:
* Excellent for persons with minimal Unix knowledge.
* Has a full complement of basic commands for file maintenance.
* Key configuration in resource file "~/.diredrc".
Weaknesses:
* Does file maintenance one file at a time with prompts.
* Fixed full screen format.
* No ANSI colorization to match color-ls.
______________________________________________________________________________________
UNIQUE FEATURES OF CRACRAFT'S DIRED 3.05
* Manual page display, DIRED 3.05 in detail.
* Key Tutor. Describe key. Execute key.
* Tag files for later processing.
* Dynamic format setup for the screen and shell commands.
* Toggle colorization of file names (4 color tables).
* Undo search and page move.
* Bookmarks.
* Abort or suspend DIRED and PUSHD to the displayed directory.
* Groff current file as a manual page.
* Type current text or binary file on terminal with pause.
* Write the formatted file list to a unique file in /tmp.
* Aliased shell commands, interactive or in resource ~/.diredset.
* Setup for shell commands attached to internal variables.
Strengths:
* Favors use by seasoned Unix people.
* Configurable screen format.
* Keys are fixed to give uniformity across different hosts.
Weaknesses:
* Key configuration is compiled into "dired" and can't be changed.
______________________________________________________________________________________
MISFEATURES OF BOTH VERSIONS OF "DIRED"
The program tends to be used for browsing and deleting files; users find the other features
too obtuse for daily use. Too many commands. Its hard to remember what key does which
command.
______________________________________________________________________________________
HOW TO GET DIRED
Find dired305.zip at http://sunsite.unc.edu/pub/Linux/. Or email to gustafson@math.utah.edu
for location of recent version.
Find Lijewski's c++ dired by sending email to lijewski@mothra.lbl.gov for location of the
recent version. If you want to see it on sunsite, then let Mike hear about it!
______________________________________________________________________________________
Copyright &copy; 1997, Grant B. Gustafson
Published in Issue 14 of the Linux Gazette
______________________________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
______________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
______________________________________________________________________________________
Directory Trees in Outline Format
By James T. Dennis jim@starshine.org
______________________________________________________________________________________
Since I frequently post messages to various Unix and Linux newsgroups and mailing lists I
often get technical questions mailed to me ``out of the blue.''
I recently received a request for a script to produce the following sort of output:
dir/
file1
file2
file
dir/
dir/
file
(etc)
Here was my quick and dirty solution:
find . | awk -F/ '{for (x=1;x<NF;x++) { printf "\t"}; print $NF}'
... which only does about 80% of the job. The only problem is that the directory entries
don't end with the ``/'' to indicate their file type. It was late -- so that's what I sent
him.
Here's how that works:
find . just prints a list of full paths (using GNU find). Some non-Linux users may have to
using 'find . -print' to accomplish this (or update to the GNU version on their systems).
awk is a text processing language/utility.
The -F (capital ``f'') sets a field separator to the '/' (slash character). Awk defaults to
parsing it's input into records (lines) of fields (whitespace delimited). Using the -F
allows me to tell awk to treat each record (still just lines) as a group of fields that are
separated by slashes -- allowing me to deal with each directory element as a separate
element very easily.
The next parameter to awk is a short program -- a for loop (like the C for() construct). It
iterates from 1 to NF.
NF in awk is the ``number of fields'' for each record. This, among many other values, is
preset by awk as it parses its input.
Awk defaults to reading it's input from a pipe or from each file listed after it's script
on the command line. We're supplying it with input through the pipe, of course.
In the body of my awk 'for' loop I simply print a tab for each directory named in that
line. This has the appearance of "wiping out" all of the leading directory names and
indenting my line as desired.
Finally, after the end of the for loop I simply print the last field ($NF). Note how the
printf takes a string similar to C's printf -- and it doesn't assume a newline. I could put
C-like format specifiers like %s and %f in there -- and I'd have to supply additional
parameters to the printf call if I did.
By contrast the awk print command (no trailing ``f'') does add an ORS (output record
separator) character to the end of its line and doesn't treat its first argument as a
format specification.
This evening I happened to be cleaning up my home directory (while procrastinating on doing
paying work and cleaning the house) I happened across a copy of this and decided to fix it.
find . | { while read i ;
do
[ -d $i ] \
&& echo $i/ \
|| echo $i
done } \
| awk -F/ '
/\/$/ { for (x = 1; x
Note that the original script: 'find ....| awk -F/ ...'
is mostly still there. But the script has gone from
one line to eleven -- all to get that silly little slash
character on the end of each directory name.
(If anyone as a shorter program -- I'd like to see it
-- there's probably a fairly quick way to do this using
perl and find2perl)
The main thing I've added is the while loop which works
like this:
find's output is piped into a group of commands
(that's what the braces are for).
That group of commands starts with a bash "while...
do" loop. The bash "while...do" loop works like this:
'while'
some command returns no error
'do'
some commands
'done'
Note that, unlike C or Pascal programming the
``condition'' for the while loop is actually any
command (or group of commands -- enclosed in
braces or parentheses). The fact that programs
return values (called errorlevels in DOS and
some Mainframe OS) makes all commands implicitly
``conditions.'' (Actually C allows a variety of
function calls within conditionals -- but we
won't go into that).
Note that some commands might not return values that
make any sense -- so those would not be suitable
for use with any of the conditional contexts in any
shell.
The command I'm using is bash' internal ``read''
command which just takes a variable name as an
argument. Note that I don't say ``read $i'' --
the shell would then fill the value of $i into
the command (i.e it would ``dereference'' it) and
the read command would have no arguments. If you
give the read command no argument it simply reads
a value and throws it away (no error).
When you set values in bash (or Bourne shell, or zsh
etc) you also don't ``dereference'' it. $i=foo would be
an error unless you actually wanted to set the
value of some variable -- whose name was currently stored
in $i to be set to foo.
Back to our script. When the find command stops printing
filenames into the pipe, the 'read i' command will fail
to get any value -- so the body of the do loop will be
skipped.
The 'do' keyword just marks the end of the list of
commands in the conditional section and the beginning
of the body of the loop (big surprise -- huh?).
The next three lines of the script are another common
shell construct --
1. [ is really an alias for or link to the 'test' command.
2. -d is a parameter to 'test' that is true if the next parameter ($i) is a directory.
3. That line ends with a ``\'' (backslash) to mark a continuation character. This causes
the shell to treat the next line as an extension of this one.
I could certainly have put all of this one line.
However, for readability I broke it up and formatted
it with leading tabs -- otherwise *I* couldn't read
it, much less expect anyone else to do so.
The next line (continuation) starts with the '&&'
operator. In bash and related shells you have things
like the familiar ``|'' (pipe) and ``;'' semicolon which are
called operators. This operator means ``if that last command
was O.K. -- returned no error -- then ...''
You can think of the '&&' operator as do this ``and''
to that (in the *conditional* sense of the the word
and).
The next line uses the '||' operator -- which is,
as you might expect, similar to the '&&' operator except
it means -- ``if the last command executed returned an
error then ...'' This is roughly analogous to the English
``or'' (again, it the conditional sense).
Of course I could have wrapped this in an 'if ....;
then ....; else...' construct -- but I'm used to the '&&'
and '||' as are most shell programmers.
So far all we've done is added a ``/'' character to the end
of each directory.
Now I'm left with a print out of full paths with directories ending in
``/'' (slashes) and other files printed normally -- back to replacing all
but the last thing with tabs -- so we pipe the 'while' loop's output
into the same awk script we were using before.
Ooops! Well, almost the same script -- it turns out that awk -F is
happy to consider the trailing slash as a blank field on the end of a
line. Hmm. O.K. we add an extra condition to the awk script.
An awk script consists of condition-action pairs. The most
common awk ``conditions'' are patterns. That is so say that they
are regular expressions (like the things you use grep to search
for). A pattern is usually delimited by slashes (a mnemonic to
the users of ed, later upgraded ex, later upgraded to vi) although
you can also ``match'' against strings that are enclosed in quotes.
Actions in awk are enclosed in braces.
Awk is an extremely forgiving language. If you leave out the
``condition'' or ``pattern'' it will execute the action on that
line for every record (line) that it comes across. That's
what my first script did.
If you leave off the action (i.e. if you have a line that
consists just of a condition) then awk will simply print
the record. In other words the default action is {print}.
When I was a regular in the comp.lang.awk newsgroup (and
alt.lang.awk that preceded it) I used to enjoy pointing out
that the shorted awk programs in the work are:
1
and
.
(The first one just prints every line it sees since ``1'' is
a ``true'' condition; the second program (a dot) prints every
line that has at least one character -- since that is the
regular expression for ``any character''. The second program
actually does filter out blank lines since awk doesn't count
the record separator as part of the line).
So, the modification of my awk script for this purpose is
to add a condition that handles any record that *ends* with a
slash. In those cases I convert all *but* the next-to-last field
to a tab, and print that ``next-to-last'' field. I also have to
add the ``/'' character to the end of that since awk doesn't consider
the field separator to be part of any field.
Finally I add a 'next' command which tells awk not to look
for any more pattern-action pairs with *this* record. If I
didn't do that than awk would execute the action for each
``directory'' line -- and also execute the other action for it
(i.e. it would print a blank line after printing each directory
line).
Is the extra 10 lines of code worth it just to add a slash to the end
of the directory names in our outline? Depends on how much your customer
is willing to pay -- or how much grief it causes you, your boss or your
users.
Mostly I decided to work on this as a training example. I think there are
some neat constructs that every budding shell programmer might benefit
from learning.
The ``find .... | {while read i .... do ... done}'' construct is well worth
remember for other cases. It allows you to do complex operations on
large numbers of files without resorting to writing a temporary file and
having to clean up after it.
When you write scripts that explicitly create temporary files you suddenly
have a host of new concerns -- what do I name it? where do I put it?
don't forget to remove it! do I have enough space for it? what if my
script gets interrupted? etc.
To be sure there are answers to each of these. For example I
suggest ~/tmp/$0.`date +%Y%m%d`.$$ for a generic temporary filename
for any script -- it gives the name of your script, the date in
YYYYMMDD format and the process ID of the current instance of your
script as the filename. It puts that into the temporary directory
under your home (which no one else should have access to). There is
virtually no chance of a name collision using this scheme (particularly
if you change the date format to +%s which is the total number of seconds
since midnight on Jan. 1, 1970). You can use the 'trap' command to
ensure that your temp files are cleaned in all but the most extreme
cases etc.
However, as I've said, it's worth understanding how to avoid temporary
files -- and usually your scripts will execute faster as a result.
The [ ... ] && ... || ... construct is absolutely essential to
any Unix sysadmin. Many of legacy scripts (particularly those in
/etc/rc.d/ -- or it's local equivalent) rely on these operators and
the test or '[' command.
Finally there is 'awk'. I've heard it argued that awk is a dinosaur
and that we should convert all the awk code to perl (and presumably most
of the Bourne shell and sed code with it). I won't argue that point
here. Suffice it to say that anything you learn how to do in awk will
just make learning perl that much easier when you get to it. awk is a
much simpler language and is phenomenally easy to integrate into shell scripts
(as you can see here).
Jim Dennis, Starshine Technical Services
_______________________________________________________________________________________________
Copyright &copy; 1997, James T. Dennis
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
[ TABLE OF CONTENTS ]
[ FRONT PAGE ]
Back
Next
_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!"
_______________________________________________________________________________________________
Welcom to the Graphics Muse
Set your browser to the width of the line below for best viewing.
&copy 1996 by
mjh
_______________________________________________________________________________________________
-->
Button Bar
-->
muse:
1. v; to become absorbed in thought
2. n; [ fr. Any of the nine sister goddesses of learning and the arts in Greek Mythology
]: a source of inspiration
W elcome
to the Graphics Muse! Why a "muse"?
Well, except for the sisters aspect, the above definitions are
pretty much the way I'd describe my own interest in computer graphics:
it keeps me deep in thought and it is a daily source of inspiration.
[Graphics Mews]
[Musings]
[Resources]
indent
T his
column is dedicated to the use, creation, distribution, and dissussion of
computer graphics tools for Linux systems.
Last month I had promised to do a review of Keith Rule's new book on
3D File Formats this month. I'll also said there would be a section
on adding fonts on Linux in last months colums. Ok, I'm a liar.
First, I decided that although Keith's book deserves some examination
I felt that another
book, Mark Kilgard's OpenGL text, had a more direct bearing on Linux
users. I'll consider taking a look at Keith's book some time in the
future.
Second, I had quite a bit of other material for January's column so
had decided to move the font discussion to February's column. However,
I forgot to update the introduction in January's column to reflect
this change. My apologies.
Now for the bad news: I had a major system crash on the 16th of
January which first of all caused me over a week of grief trying
to recover and second caused the loss of a large number of files.
No, I wasn't doing backups. So shoot me. I managed to recover an
earlier copy of this months Muse column from a laptop I have, but
I lost a good portion of what I'd already done. Now, as I write this,
I have 3 days to get the column done and uploaded. The result is
that the book review and a number of other items will have to be put
off till another time.
So, does anyone have a decent tape backup system that can run on
ftape drives?
In this months column I'll be covering, along with how to add fonts to
your system:
* a GIF Animations update: the MultiGIF program
* some Printer info I gathered in the past month
* tkPOV V2.0 - a graphical front end to POV-Ray 3.0
NOTE:
I lost all my old email and mail aliases when my system went down. If
you have been in touch with me in the past and want to stay in touch
please send me some email
(mjhammel@csn.net)! I'm particularly interested in hearing from
Paul Sargent, who was helping me with my look into BMRT. I lost
your email address Paul, along with all the messages we'd exchanged on
the BMRT article series! Write me (or if you know Paul, please have
him contact me)!
Graphics Mews
Disclaimer:
Before I get too far into this I should note that any of the news items I
post in this section are just that - news. Either I happened to run
across
them via some mailing list I was on, via some Usenet newsgroup, or via
email from someone. I'm not necessarily endorsing these products (some of
which may be commercial), I'm just letting you know I'd heard about
them in the past month.
xfig 3.2.0 Beta available
Xfig is a menu-driven tool that allows the user to draw
and manipulate objects interactively in an X window. The
resulting pictures can be saved, printed on postscript
printers or converted to a variety of other formats (e.g. to
allow inclusion in LaTeX documents).
xfig is available on ftp.x.org in
/contrib/applications/drawing_tools/xfig.
You also need a JPEG library, which can be found in /contrib/libraries.
and TransFig version 3.2.0-beta1. TransFig contains the postprocessor
needed by xfig to convert fig files to one of several output formats,
such as PostScript, pic, LaTeX etc. The TransFig package is in the
directory
/contrib/applications/drawing_tools/transfig.
indent
indent
Alexander Zimmermann has uploaded another update to his ImageMagick package.
ImageMagick (TM), version 3.7.9, is a package for display and
interactive manipulation of images for the X Window System.
The package has been uploaded to sunsite.unc.edu:/pub/Linux/Incoming
as:
* ImageMagick-3.7.9-elf.lsm
* ImageMagick-3.7.9-elf.tgz
ImageMagick supports also the Drag-and-Drop protocol form the
OffiX package and many of the more popular image formats including
JPEG, MPEG, PNG, TIFF, Photo CD, etc.
You will also need the package libIMPlugIn-1.0-elf to get it working.
These can be retrieved from
ftp.wizards.dupont.com
/pub/ImageMagick/binaries.
indent
World Movers, the first VRML 2.0 Developer Conference
I received the following information via email (unsolicited, but
its probably the first time I got something I found really
interesting via a blind email post). Note that I have nothing
to do with this conference, other than I wish they'd invite me to go -
expenses paid, of course:
World Movers, the first VRML 2.0 Developer Conference, will be held on
January 30 and 31 at the ANA Hotel in San Francisco, CA.
At World Movers you will:
* Select from sessions in three key tracks over two days
+ Content Creation
+ Business Applications of VRML
+ Future Directions and Current Technologies
* Learn how to create great VRML 2.0 content and applications
* See and learn about real applications that use VRML
* Find out about the latest tools for VRML 2.0
With a pan-industry advisory board and a wide array of hosts and
participants, World Movers will give you a complete picture of VRML 2.0
content and applications from all perspectives.
Register by calling (800)488-2883 or (415)578-6900, or go online at
http://www.worldmovers.org.
indent
PNG Magick Plug-in 0.8
There is a new plug-in for Unix/Linux versions of Netscape called
PNG Magick Plug-in 0.8. This plug-in supports
the following file formats:
PNG, XPM, TIFF, MIFF, TGA, BMP, PBM, PGM, PPM, PNM, PCX,
FITS, XWD, GIF, JPEG, WAV and MPEG-1. It is reported to support
Drag and Drop capabilities as well.
For MPEG-1 support you need the Xew library which doesn't seem
to work well with the Linux version of this plug-in.
PNG Magick Plug-in 0.8
is published under the GNU General public License and is available at
http://home.pages.de/~rasca/pngplugin/.
indent
indent
TkFont v1.1
There is a new tool for viewing fonts on Linux. I haven't tried
this yet so I don't know how well it works. It has been uploaded
to
tsx-11.mit.edu in the /incoming directory.
The file-name is `tkfont-1.1.tar.gz'.
indent
Version 0.1.8 of Lib3d is now available from Sunsite.
Lib3d is a high performance 3d C++ library distributed under the GNU
LGPL. Lib3d implements sub-affine texture mapping, Gouraud shading
and Z-buffer rasterization, with support for X11, DGA, SvgaLib and DOS.
Lib3d is available from
ftp://sunsite.unc.edu/pub/Linux/Incoming/lib3d-0.1.8.tar.gz
For more information:
http://www.ozemail.com.au/~keithw
indent
CFP: ACM SIGGRAPH 97 Sketches Program
Deadline: April 16, 1997
The following was posted in a number of places. I got it via a
friend on the Gimp User mailing list. I have no association with
SIGGRAPH (unfortunately) so can offer no other details than the
following:
SKETCHES are live, 15 minute presentations that provide a forum for
unique, interesting ideas and techniques in computer graphics.
Sketches allow the presentation of late-breaking results, works in
progress, art, design, and innovative uses and applications of
graphics techniques and technology. Sketch abstracts will be published
in the Visual Proceedings.
Sketches are a fun, educational, high-profile way to show your work
and creations. We are seeking submissions in four areas:
* Animations
* Applications
* Art and Design
* Technical
For more information, see the SIGGRAPH 97 Call for Participation, send
email to
sketches.s97@siggraph.org,
or for the latest, most
comprehensive information on how to submit to Sketches and other
SIGGRAPH 97 programs, including supplemental documents, please go to:
http://www.siggraph.org/s97/.
To request a copy of the Call for Participation, contact:
SIGGRAPH 97 Conference Management
Smith, Bucklin & Associates, Inc.
401 North Michigan Avenue
Chicago, Illinois 60611 USA
+1.312.321.6830
+1.312.321.6876 fax
siggraph97@siggraph.org
DEADLINES:
16 April 1997
5 pm Eastern Daylight Time
Final Sketch proposals
To discuss your concepts and ideas for Sketches, contact:
David S. Ebert
SIGGRAPH 97 Sketches Chair
University of Maryland Baltimore County
CSEE Department ECS-210
1000 Hilltop Circle
Baltimore, Maryland 21250 USA
+1.410.455.3541
+1.410.455.3969 fax
sketches.s97@siggraph.org
indent
indent
indent
Did You Know?
The
VRML 2.0 Specification, Moving Worlds
from SGI, provides for
"spatial audio"? This is a definition of how sound is played
in relationship to your point in space and distance from an object
which has a sound attached to it. The O2 system from SGI has
a VRML browser which was demonstrated on Part 2 of PC-TV's series
on Unix which covered commercial Unix options. Part 3 of this
series started airing at the end of January and is devoted to
our favorite OS - Linux!
There is a wonderful description on using color palettes with
Web pages at
http://www.adobe.com/newsfeatures/palette/main.html. The page
is a reprinted article by Lisa Lopuck from Adobe Magazine and is
quite detailed. Check it out!
Have you been thinking about using POV-Ray 3.0's new caustics
feature? Are you unsure exactly what it does? Want to learn all
about it? Then check out
The Caustic Tutorial for POV. This is a very detailed
explanation on what caustics are and how to use them.
Briefly,
caustics are formed when light is either focused or dispersed due to passing through
media with different indices of refraction. Bright spots in the shadows are where light
is focused and dark spots are where the light has been dispersed.
Thanks to
Paul R. Rotering for this description (taken from the IRTC-L
mailing list).
Q and A
Q: What is displacement mapping?
A: Displacement mapping is not only the perturbing of the surface
normal of an object, like a bump maps do, but in fact a distorting
of the object itself. You can think of it
as a height field over an arbitrary surface. The latest version of
BMRT is reported to support displacement maps. Few other
publicly available renderers provide this feature.
Q:
I have just downloaded the complete batch of plug-ins from the
"Plug-in Registry", and noticed that the "interpolate",
"lightest" and "darkest" plug-ins appear to do the same thing
as the "blend",
"add" and "multiply" channel ops respectively. Is this correct, or is
there some difference under certain circumstances?
A:
Not exactly. Blend uses integer values and restricts you to
interpolation. Interpolate/Extrapolate uses floating point values and
does not restrict the range of the blending value --- you can do
extrapolation, too (look at my home page for some examples):
http://www.nuclecu.unam.mx/~federico/gimp
Lightest and Darkest pick the lightest and darkest pixels from two
images. It is not the same as add and multiply except for bilevel
images.
Both of these questions were answered by Mena Quintero Federico,
aka Quartic, on the Gimp User mailing list.
indent
indent
indent
Musings
GIF animations update: MultiGIF
After my first column (Linux Gazette, issue 12),
Greg Roelofs
wrote me to tell me about another tool for creating animated
GIF images. Andy Wardley's
MultiGIF
allows the use of sprite images as part of the animation. Sprite
images are like small sections of an image. Instead of
creating a series of GIF images that are all the same size and simply
appending each one at the end of the other (as WhirlGIF does) the user can
create an initial image along with a series of smaller images that are
positioned at offsets from the upper left corner of the full image.
By using sprites (I'm not completely sure what a sprite
really is, but Greg used this term and it appears similar to other
uses I've seen - someone correct me if its not the correct use of
the term) the GIF animator can reduce the file size anywhere from
a factor of two to a factor of 20 in size. As proof, Greg offered
his animated
PNG-balls, which went from 577k to 233k in size.
Another animation, a small horizontally oscillating "Cylon eyes"
(referring to the old Battlestar Gallatica metal menace), provided
a savings of a factor of 20.
MultiGIF comes with C source code and is shareware. Andy only asks
that you provide a donation if you find you are using it frequently.
There is also a utility called gifinfo which can be used to identify
GIF files, including multiframe GIF animations.
Both WhirlGIF and MultiGIF come with fairly decent documentation
describing how to use the various command line options. About the
only thing that might be missing is why you would use one option over or in
conjunction with another, but thats a minor point. I find the use of
sprites with MultiGIF and its smaller output files more useful to me.
However, new users who are not quite familiar with how to create sprites
(including transparency) with tools like the Gimp might prefer the simpler
WhirlGIF.
indent
Adding Fonts to your system
Fonts are used extensively for creating graphics images.
Many of the graphics on my Web pages and in the
Graphics Muse use fonts I've installed from
collections of fonts on commercial CDs.
Fonts are also used for ordinary text in X applications, from
the fonts in your xterm to the title bars provided by your
window manager to the pages displayed by xman.
The difference is hard to distinguish, but
whether used for ordinary text or to create
outrageous graphics, adding fonts to your system and letting
your X server know about them is the first step .
Just so you know: nearly all X applications accept the "-fn"
and/or "-font" command line arguments. This is a feature built into
the X Windows API. How this is used depends on the application. For
xterms, just use "-fn " to specify the font used in the
xterm window. This does not specify what font to use for the xterm
title bar. That is controlled by the window managers X resources.
To know what fonts are available on your system you can look
under the font directories for fonts.alias files. There is supposed to be
one of these in each directory under
/usr/X11R6/lib/X11/fonts,
but whether there is or not depends on the distribution you're using.
The name to use is the
name on the left. For example, under
/usr/X11R6/lib/X11/fonts/misc,
in the file fonts.alias there is the following line:
5x7
-misc-fixed-medium-r-normal-
-7-70-75-75-c-50-iso8859-1
To use this font with xterms I would do:
xterm -fn 5x7
You can actually use the string on the right, but unless you understand
how fonts are defined you probably don't want to do this.
I don't want this to turn into an X Windows column. There are other
places for such discussions, and I'm sure LG could use a regular
columnist for X. But this column is about computer graphics so
this is all I'm going to say about using fonts in X applications
from the X resources standpoint. In any case, since the X server
is being used to handle the fonts, adding fonts to
your system is the same whether you use them for graphics or as
X resources.
Suppose you had a font called westerngoofy that you
wanted to use in the Gimp as the start
of some neat title graphic for a Web page.
By default there isn't an entry in any of the fonts.alias files
for westerngoofy, so when you use the text tool in the Gimp
it won't show up in the list of available fonts.
There are 3 steps to making this font available for use with the
Gimp:
* Grab the fonts and place them in a local directory
* Configure that directory for use as a font directory
* Tell the X server about this new font directory
The first part is simple - grab a copy of the font file and put it
in some directory. Make sure you've uncompressed it if the archive
you retrieved the file from compresses the fonts. Most X servers
don't understand compressed fonts (some do, but all understand
uncompressed fonts). The directory can be owned by anyone. It does
not have to be a directory under the system fonts directories
(generally these are under
/usr/X11R6/lib/X11/fonts). On my system I have a "src/X11"
-Top of next column-
indent
indent
indent
More Musings...
* Printer Info - my journey into color printing
* tkPOV V2.0 - a graphical front end to POV-Ray 3.0
indent
indent
indent
directory under my home directory. Under this I created a "fonts"
directory where I put new fonts that I find. If you are the owner
of your system and have root access you might want to put the fonts
under /usr/local/fonts or someplace similar.
Note that since TrueType fonts are not supported by default by most
X servers we won't concern ourselves with how to use them here. The
font format you should be using are Type1 fonts. There are plenty
of places to get these, including numerous CD-ROMs available from
any decent computer software stores. Some online resources are
listed in the
Linux Graphics mini-Howto under the "Other Topics" section.
Next you need to configure your new fonts directory so that the
X server can provide you FontName-to-File mappings. To do this you
need to get hold of a little Perl script called
type1inst,
which is short for "Type 1 Install". This script is easy to use and comes
with documentation explaining what you about to do. Basically,
you run the script to create a couple of files, fonts.alias and
fonts.dir, which the X server uses to associate a fonts name to
the font file. You can also use mkfontdir, but I like
type1inst
better. mkfontdir doesn't always seem to be available
on all platforms and finding a binary version (or even source)
has never been easy for me (I think its buried in the X11 source
tree, which I really don't want to download just for one program).
The last step is to let the X server know about the new font
directory. The xset command allows a user to configure
a number of options for the X server. One of these options is
the paths to search for font files. The format of the command
is as follows:
xset fp+ &ltpath&gt
The fp option is used to modify the font path. The plus
sign is used to add a font path. Because the plus sign is after
the fp the font path specified will be appended to the
current list of paths, if any. Using +fp would prepend
the new path to the front of the current list. There are other
possibilities. Running
xset -?
will provide a thorough list of options. The man page for xset
also contains good descriptions of the options.
Now that the server knows where to look, it has to be told to
go ahead and check for fonts in the new directories. The
rehash option to xset does this. Simply run
xset rehash
and your new fonts are ready for use!
Of course, once you've installed the fonts in a directory and
run type1inst you can put the xset commands in your
.xinitrc file so they are run every time you start up your X
environment (such as with the startx script). This is what
I do so that I always have access to the set of fonts I've installed
from CD-ROMs or from font archives from the net.
Thats all there is to it. You should now be able to use your fonts
with tools like the Gimp or XPaint in order to create lots of
interesting logos for Web pages. Enjoy!
Resources
The following links are just starting points for finding more information
about computer graphics and multimedia in general for Linux systems. If
you have some application specific information for me, I'll add them to my
other pages or you can contact the maintainer of some other web site. I'll
consider adding other general references here, but application or site
specific information needs to go into one of the following general
references and not listed here.
Linux Graphics mini-Howto
Unix Graphics Utilities
Linux Multimedia Page
Some of the Mailing Lists and Newsgroups I keep an eye on and where I get alot
of the information in this column:
The Gimp User and Gimp Developer Mailing Lists.
The IRTC-L discussion list (I'll get an address next month).
comp.graphics.rendering.raytracing
comp.graphics.rendering.renderman
comp.os.linux.announce
Future Directions
Next month:
* BMRT Part I: An Introduction - creating a simple scene and rendering it
* Scanner Info
* Height Fields with HF-Lab
* Review: TkPOV - a POV-Ray scene file editor
* Book Review: OpenGL Programming for the X Window System
Let me know what you'd like to hear about!
_______________________________________________________________________________________________
Copyright &copy; 1997, Michael J. Hammel
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
[ TABLE OF CONTENTS ]
[ FRONT PAGE ]
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_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
Linus Torvalds to Receive Annual UniForum Award
By Richard Shippee, dick@uniforum.org
_______________________________________________________________________________________________
Fri, 31 Jan 1997
Linus Torvalds, considered the "Father of the LINUX Operating System",
has been selected by the UniForum Board of Directors to receive The UniForum
Award. The Award will be presented to Torvalds on Thursday, March 13th, as
part of the morning Keynote Session at UniForum '97, being held at the Moscone
Convention Center in San Francisco.
The UniForum Award, presented annually since 1983, goes to individuals or
groups whose work has significantly advanced the cause of open systems over
time, or has had an immediate and positive impact on the industry with long
term ramifications. The UniForum Board of Directors considered a number of
nominees for this year's awards, and voted unanimously in their selection of
Linus Torvalds for his breakthrough work on the LINUX kernel and for his
pioneering efforts in making his work available at little or no cost to anyone
wishing to develop on it.
Linus Torvalds is the creator and chief architect of the Linux operating
system. At the University of Helsinki in the spring of 1991, frustrated
with the price of
Unix operating systems, Torvalds began writing some software code to handle
certain computing chores on the 386.
"I noticed that this was starting to be an operating system," he
says.
Since then, he has traveled all over the world promoting Linux.
Although developing Linux has been almost a full-time job for him,
he recently accepted a job at Transmeta in Santa Clara, California.
He and Tovi Monni recently celebrated the birth of their baby daughter,
Patricia Miranda Torvalds.
The UniForum Board also selected a second Award winner this year: James
Gosling of JavaSoft, and his development team, for their work on Java. Gosling
will receive his Award at the Wednesday, March 12th Keynote session at
UniForum '97.
The Award presentation to Linus Torvalds, at the Thursday Keynote session, is
open to all free of charge but requires attendees to register for UniForum
'97. Registrants may also visit the exhibits floor which features booths from
a number of LINUX vendors including Comtrol, LINUX International; SSC,
publishers of Linux Journal; Red Hat Software and Work Group Solutions. To
view the entire UniForum '97 Conference and Trade Show brochure, and to
register on-line, please go to
http://www.uniforum97.com/.
For additional information contact:
Richard Shippee, Director of Communications, UniForum
408-986-8840, ext 17, dick@uniforum.org
_______________________________________________________________________________________________
Copyright &copy; 1997, Richard Shippee
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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[ FRONT PAGE ]
Back
Next
_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
Linux Security 101
By Marsala, mars@loeffel.txdirect.net
_______________________________________________________________________________________________
You can jump down to the section on tcpd
Or take a peek at the other stuff you need to keep an
eye on.
_______________________________________________________________________________________________
Ok. You've got Linux beat. You finally got AfterStep set up the way you want
it, you've managed to set up ip masquerading for your home LAN, you've managed
to set up a cool issue for people to see when they log in, you managed to
convert a couple over to the One True OS, and chicks really dig you because,
as we all know, Linux geeks are sexy.
One night as you're peeking at /var/adm/messages, you notice that
someone from some place you've never heard of before tried to make 5 ftp
connections, 6 telnets, and even an nntp connection. What's up with that?
Well, Linux (and all Unix type OS's in general) were designed to be a
programmer's paradise. The same qualities that makes Linux such a wonderful
networking and hacking operating system also expose a few security holes.
There are a few programs that you probably rely on or use daily that can be
used to gain root access (which is a Bad Thing). What's worse, the commercial
distributions that many Linux users depend on have these programs with
security holes inside packages that are installed as part of the base
system.
That's the bad news. The good news is that we can make it tougher for the
Bad Guys to do their dirty deeds. By checking the
Linux ALERTS
page, you can find out what the holes we know about are, and how to
temporarily plug them up or even fix them up for good. There is also a nice
little tool that is probably on your system that we can use to keep them
from even having access to our machine.
And that's what I'm going to focus on. My belief here is that if we can
keep the Remote Bad Guys (people who don't have legitimate access to our
machines) out, then we only have to worry about the Local Bad Guys (if any).
Plus it gives us a chance to fix anything on our machine that is a security
hole the RBG's can use.
_______________________________________________________________________________________________
tcpd
_______________________________________________________________________________________________
There's a daemon that's probably been installed on your machine that you don't
know about. Or at least, you're not aware of what it can do. It's called
tcpd, and it's how we shut off access to some of the basic services
that the Bad Guys can use to get on our system.
Since tcpd can be pretty complex, I'm not going to go into all the
details and tell you how to do the fancy stuff. The goal here is to keep the
mischievous gibbons from knocking down what it took so long for use to set
up.
tcpd is called into action from another daemon, inetd, whenever
someone tries to access a service like in.telnetd, wu.ftpd, in.fingerd,
in.rshd, etc. tcpd's job is to look at two files and determine if
the person who is trying to access the service has permission or not.
The files are /etc/hosts.allow and /etc/hosts.deny. Here's
how it all works:
1. Someone tries to use a service that tcpd is monitoring.
2. tcpd wakes up, and makes a note of the attempt to the syslog.
3. tcpd then looks hosts.allow
+ if it finds a match, tcpd goes back to sleep and lets the user access the service.
4. tcpd now takes a look at hosts.deny
+ if it finds a match, tcpd closes the user's connection
5. If it can't find a match in either file, or if both files are empty, tcpd shrugs,
guesses it's OK to let the user on, and goes back to sleep.
Now, there are a couple of things to note here. First, if you haven't edited
hosts.allow or hosts.deny since you installed Linux, then
tcpd assumes that you want to let everyone have access to your machine.
The second thing to note is that if tcpd finds a match in
hosts.allow, it stops looking. In other words, we can put an entry
in hosts.deny and deny access to all services from all machines, and
then list ``friendly'' machines in the hosts.allow file.
Let's take a look at the man page. You'll find the info you need by typing
man 5 hosts_access (don't forget the 5 and the underscore).
daemon_list : client_list
daemon_list is a list of one or more daemon process names
or wildcards
client_list is a list of one or more host names, host
addresses, patterns or wildcards that will be matched
against the remote host name or address.
List elements should be separated by blanks and/or commas.
Now, if you go take a look at the man page, you'll notice that I didn't show
you everything that was in there. The reason for that is because the extra
option (the shell_command) can be used to do some neat stuff, but *most
Linux distributions have not enabled the use of this option in their tcpd
binaries*. We'll save how to do this for an article on tcpd itself.
If you absolutely have to have this option, get the source from
here and recompile.
Back to business. What the above section from the hosts_access man
page was trying to say is that the format of
hosts.[allow|deny] is made up of a list of services and
a list of host name patterns, separated by a ``:''
You'll find the name of the services you can use by looking in your
/etc/inetd.conf...they'll be the ones with /usr/sbin/tcpd
set as the server path.
The rules for determining host patterns are pretty simple, too:
* if you want to match all hosts in a domain, put a ``.'' at the front.
+ Ex: .bar.com will match "foo.bar.com", "sailors.bar.com", "blue.oyster.bar.com",
etc.
* if you want to match all IPs in a domain, put a "." at the end.
+ Ex: 192.168.1. will match "192.168.1.1", "192.168.1.2", "192.168.1.3", etc.
And finally, there are some wildcards you can use:
* ALL matches everything. If in daemon_list, matches all daemons; if in client_list, it
matches all host names.
+ Ex: ALL : ALL would match any machine trying to get to any service.
* LOCAL matches host names that don't have a dot in them.
+ Ex: ALL : LOCAL would match any machine that is inside the domain or search
aliases given in your /etc/resolv.conf
* except isn't really a wildcard, but it comes in useful. It excludes a pattern from the
list.
+ Ex: ALL : ALL except .leetin-haxor.org would match all services to anyone who is
not from ``*.leetin-haxor.org''
Ok. Enough technical stuff. Let's get to some examples.
Let's pretend we have a home LAN, and a computer for each member of the family.
Our home network looks like this:
linux.home.net 192.168.1.1
dad.home.net 192.168.1.2
mom.home.net 192.168.1.3
sis.home.net 192.168.1.4
bro.home.net 192.168.1.5
Now, since no one in the family is likely to try and ``hack root,'' we can
assume they're all friendly. But....we're not so sure about the rest of
the people on the Internet. Here's how we go about setting things up so
people on home.net have full access to our machine, but no one else does.
In /etc/hosts.allow:
# /etc/hosts.allow for linux.home.net
ALL: .home.net
And in /etc/hosts.deny
# /etc/hosts.deny for linux.home.net
ALL : ALL
Since tcpd looks at hosts.allow first, we can safely deny
access to all services for everybody. If tcpd can't match the machine
sending the request to ``*.home.net'', the connection gets refused.
Now, let's pretend that Mom has been reading up on how Unix stuff works,
and she's started doing some unfriendly stuff on our machine. In order
to deny her access to our machine, we simply change the line in
hosts.allow to:
ALL: .home.net except mom.home.net
Now, let's pretend a friend from....uh....friend.com wants to get something
off our ftp server. No problem, just edit hosts.allow again:
# /etc/hosts.allow for linux.home.net
ALL: .home.net except mom.home.net
wu.ftpd: .friend.com
Things are looking good. The only problem is that the name server for
home.net is sometimes down, and the only way we can identify someone as
being on home.net is through their IP address. Not a problem:
# /etc/hosts.allow for linux.home.net
ALL: .home.net except mom.home.net
ALL: 192.168.1. except 192.168.1.3
ALL: .friend.com
And so on....
I have found that's it's easier to deny everybody access, and list your
friends in hosts.allow than it is to allow everybody access, and
deny only the people who you know are RBG's. If you are running a private
machine, this won't really be a problem, and you can rest easy.
However, if you're trying to run a public service (like an ftp archive of
Tetris games for different OS's) and you can't afford to be this paranoid,
then you need shouldn't put anything in hosts.allow, and just put
all of the people you don't want touching your machine in hosts.deny
You might also want to take a look at the next section.
_______________________________________________________________________________________________
Other things to keep in mind
_______________________________________________________________________________________________
Security holes in software
Like I said earlier, a lot of the software that comes standard in CD-ROMs have
security holes in them which could let local or even remote users execute
commands as root on your system. Keep an eye on
Linux ALERTS
to find out about problems we know about and how to fix them.
What services you offer
Check to make sure that the services you have running on your machine are
what you really want to offer. For example, most of us don't have a need
to run in.nntpd, yet it's got an entry in /etc/inetd.conf.
Do you really want everyone on the Internet to have access to
in.fingerd? Do you really need to let everyone on the Internet have
access to your ftp server?
Find what you don't need (or don't want to offer to any passing stranger who
might happen across your machine) and either shut it down or deny outside
access to it.
Passwords
Yeah, yeah, yeah. Everyone's heard the speech about passwords, but they
are pretty important. Especially if you're not restricting access to your
machine. Remember, if they can get to your machine, they can get on your
machine. And if they can get on your machine, they can get root access.
In case you haven't heard the speech, here's the condensed version:
1. Make the passwords at least 8 characters long.
2. Mix the case of the passwords.
3. Use at least one numeral.
4. Use at least one non-alphanumeric character.
5. Change the passwords on a regular basis. About once every
two months should do for the casual user.
I have found that using "k-rad" or "leet-speak" helps when you need to
make up a password. For example, instead of using the password
"foobar", try using "f00b4R!".
Lastly, get and install shadow passwords. You might have to recompile a
few services, but it's worth the extra protection.
File Permissions
Many of the security holes that exist are because the files are "setuid".
That means that a non-root user can execute the files as root. Remove
this permission from any files that don't need it. Like mount.
It really isn't that much of a hassle to keep one of your virtual
consoles logged in as root, and flip over to it when you need to get
something done.
Also, if you have stuff sitting somewhere that you don't want anyone else
to see, don't give them world rwx permission on the dir.
Keep an eye on the syslog
At least once a day, you need to go check the syslog and see what's been
happening. You can find it /var/adm/syslog, and I'd also recommend
taking a peek at /var/adm/messages. You'll want to look for
multiple connections coming from places you don't know in a short period
of time. If they look suspicious, then don't hesitate to slap an entry
for the domain into /etc/hosts.deny
Who you trust
This is just common sense. It's not a wise idea to give out your root password
to someone you just met on IRC 5 minutes ago who claims they can get Apache
up and running on your system if you just tell them the root password.
Set up a guest account with limited read, write, execute abilities and let them
use that.
It's also not wise to let people just log in and fiddle around on your machine.
Despite common belief, it is possible to create Unix ``viruses,'' and all you
really need is the knowledge, the will, and an opportunity. For more
information, see the paper on
The Plausibility of
Unix Virus Attacks
_______________________________________________________________________________________________
FINAL WORD
To be completely honest with you, the only way to be 100% sure your machine
can't be compromised is to physically deny access to it. That means get
rid of the modem and ethernet card, fill up any hole in the computer's case
with cement, and buy a big, mean pit bull to guard it while you are asleep.
Well, maybe that's going a bit far. But the point is, if they can't get to
your machine, they can't do anything to it. If you think your machine has
been compromised, disconnect it from the network, look through the
syslog, try to find out how it was compromised, fix the problem,
set all new passwords for your accounts, and then reconnect it.
We might not be able to make the machine 100% secure, but we can make
it hard for the Bad Guys to do their thing.
_______________________________________________________________________________________________
Email:
mars@loeffel.txdirect.net
_______________________________________________________________________________________________
Copyright &copy; 1997, Marsala
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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[ FRONT PAGE ]
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_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
THE MUTT MAILER
by Larry Ayers
_______________________________________________________________________________________________
Introduction
Michael Elkins is a programmer who at one time was involved in the
development of the venerable mail-client, Elm. He had some ideas which he
would have liked to include in Elm but for whatever reasons the other Elm
developers weren't receptive. So he struck out on his own, creating a
text-mode mailer which incorporates features from a variety of other
programs. These include other mailers such as Elm and Pine, as well as John
Davis's Slrn newsreader. As an indication of the program's hybrid nature
he has named it Mutt. Although the mailer began as an amalgamation of
features from other programs, it has begun to assume an identity of its own.
Mutt has been in beta-testing for several months now and new versions
have been released regularly. Lately I've noticed that binary packages have
been appearing in the Sunsite incoming directory, which I take as a sign
that the program is now deemed ``suitable for a general audience.'' I have
found that it compiles cleanly and works dependably.
Distinguishing Characteristics
The composition of messages has always been a thorn in the side of
developers of mail clients. After all, a usable mailer is the goal, not
a text editor. The typical approach has been to include a simple message
composition editor (such as Pico in Pine) and allow the option of starting an
external editor of the user's choice. This has certain drawbacks. If in the
middle of a message you need an editing function not included by the internal
editor, it can be distracting and awkward to switch boats in midstream, so to
speak.
This minor dilemma is neatly side stepped by Mutt; there is no internal
editor included. All message composition is done with a familiar editor,
preferably a text-mode one so that Mutt can be run at the console as well as
under X-windows. As an example, I've set Mutt up to use Vile with a
message-specific rc-file (sets word-wrap, etc).
Mutt can be compiled with a feature unusual in text-mode mail clients:
it can fetch mail from a POP server, a duty which is more commonly assigned to
an external agent such as Popclient. Compile-time support is also available
for PGP-encrypted messages, though theoretically this is only available for
US citizens.
A few of Mutt's other features include:
* Configurable colorization of various screen elements, such as headers, sigs, and
foreground/background.
* Message sorting options
* Small executable size (around 150 kb. on my system)
* MIME support
* Message threading
* Indefinite postponement of outgoing messages
* Can use either curses/ncurses or S-lang as the screen library
* Customizable keybindings
* Delivery Status Notification (DSN) support
Mutt can be run from the command line, if you just want to mail a quick
message without having to load your mail-spool file. Incidentally, Mutt uses
the mailx (single-file) message format, so the transition from Pine or Elm
is painless.
If you've ever used the Jed editor or Slrn the appearance of Mutt will be
familiar. Like these programs Mutt is easy on the eyes, and the amount of
coloring used is easily controlled. The documentation supplied with Mutt is
very complete, but this isn't one of those programs which takes long to learn.
Obtaining Mutt
Binary versions of Mutt are available from the Sunsite archive site,
currently in pub/Linux/Incoming. I recommend obtaining the source
from the Mutt home site, where the
latest versions will first appear. Compiling it yourself allows the program
to be tailored to your needs; there are several compile-time options.
The non-export version, which contains PGP/MIME support, is
export-controlled; U.S. citizens can read the file README.US-only and follow
the directions to access the files. The non-export version has been
exported anyway (against the author's wishes), and can be obtained from the
following sites:
* ftp.teuto.de/pub/user/lmb
* ftp.fu-berlin.de/pub/unix/mail/mutt/mutt-pgp
_______________________________________________________________________________________________
Why not give it a try? The source file is small, and compilation and
installation just takes a few minutes. I think you'll like it.
_______________________________________________________________________________________________
Larry
Ayers
Last modified: Fri Jan 24 18:54:25 CST 1997
_______________________________________________________________________________________________
Copyright &copy; 1997, Larry Ayers
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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_______________________________________________________________________________________________
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_______________________________________________________________________________________________
WINDOW-MANAGER NEWS
by Larry Ayers
Window-managers seem to be unique to unix-derived operating systems.
Rather than assuming all windowing/GUI tasks, the X-server confines itself
to the basic grunt-work of facilitating communications between the graphics
hardware and the kernel. This is typical unix behavior, in which complex
tasks are broken up into sub-tasks performed by separate programs. This is
beneficial to the end-user. If something goes wrong in such a system it is
easier to place blame and isolate the problem; flexibility and
configurability are also much greater than in systems in which the graphic
interface duties are intertwined inextricably with basic kernel
functions.
The end result of this is that if you start the X-server ``bare'' (without a
window manager) you will see borderless windows on a gray and black stippled
background. Few people want this appearance, so over the years a wide variety
of window-managing software has been developed. Some are proprietary, but in
the free software world there are several active projects, a few of which I'll
discuss in this article.
_______________________________________________________________________________________________
FVWM
The F(?) Virtual Window Manager is, for several good reasons, the most
commonly used Linux window manager. It was originally an offshoot of an early
manager called Twm, but has evolved considerably in recent years.
Rob Nation, who was also partially responsible for top and rxvt, was the
maintainer of the 1.xx versions of Fvwm. This series reached a developmental
plateau a few years ago and a new group of developers adopted the program and
initiated the 2.xx series. The 1.xx versions are stable and reliable and are
still being used by many people, though they aren't actively maintained.
I won't go into the basic features of Fvwm, as this topic has been
well-covered (by John Fisk and others) in past issues of the Gazette. Since
those articles appeared there have been many new features and modules added to
Fvwm, a few of which I'll describe.
By the way, don't be put off by the beta status of the 2.xx versions;
since about version 2.0.37 the program has been relatively easy to compile and
free of any but very minor bugs. Version 2 is asymptotically approaching a
major release which will be version 2.1.
New Features
I can't help but think that the developers working on Fvwm2 are keeping an
eye on the upstart Afterstep window-manager, which is based on Fvwm2 code.
The newest Fvwm2 release (as of Jan 24,1997) is 2.0.45; patches have been
incorporated which give Fvwm2 some of the nicer decorative features of
Afterstep. These include tiled pixmaps for window-borders and title bars, as
well as gradient-shading of the title bar from one color to another. Another
addition is the ability to use mini-icons for title bar buttons. If you're not
interested in such decorative elaborations they can be easily disabled by
editing the fvwm.tmpl file before compilation. The new release is
worth obtaining even if you don't care about the new visible features, as many
bugs have been fixed. The man-page has also been expanded and updated to
cover these changes.
It's now possible to write Fvwm modules in either Perl or Python. Several
examples of each are included in the distribution, which is available from
this Hawaiian site.
_______________________________________________________________________________________________
Afterstep
If you are fond of the appearance of the NExtstep operating system, you'll
probably like Afterstep. This is an offshoot of Fvwm2 development which has
attracted much attention recently in the Linux community, to the point where
it is being included (despite its beta status) in some newer distributions.
Afterstep pioneered the use of pixmaps and mini-icons in borders and
title-bars, as mentioned in the Fvwm2 section above. But the major difference
is the Wharf module, a very configurable tool bar which uses larger-than-normal
icons (64x64). The supplied icons are very stylish, and can be configured to
have gradient-shaded backgrounds. As with the Fvwm2 Buttons module, the Wharf
(NExt calls it a ``dock'') can ``swallow'' applications and other modules. Lately
modules designed to be swallowed by the Wharf have become available from the
Afterstep web-sites. Among these are a PPP dialer, a CD-player, and a mixer.
Check out the Afterstep
Home Page for the latest news and releases.
_______________________________________________________________________________________________
Wm2
Possibly as a reaction to the growing number of unnecessary features in the
other window-managers,
Chris
Cannam has written a minimalist window-manager called Wm2. This small and
fast window-manager was inspired by the Plan 9 manager, which is part of the
experimental Plan 9 operating system. There are no icons, virtual desktops,
or configuration files, in stark contrast to the other managers discussed
here, just nicely framed windows and a simple menu which starts an xterm and
lists active and hidden windows. The windows are framed in a distinctive
manner, with no top title bar. Instead a shaped tab protrudes from the top of
the left side of the window with the title displayed vertically.
Rather than include a screen shot of Wm2 in action, here are links to the
Wm2 web page which has links to both a screen shot and the source itself:
The Wm2 Page (local)
The Wm2 Page (WWW)
Wm2 is still relatively new; I have noticed that it stresses the X-server
more than would be expected of such a small application, possibly because of
its use of the shaped-window X-extension. Screen refreshes seem to be slow.
Nonetheless in this third version it seems to be stable, and it provides a
refreshing contrast to the complexity of the other window-managers. The only
configuration involved comes before compilation of the source. The various
colors and preferred terminal emulator can be set in the Config.h file;
after installation the only way to change these settings is to re-edit and
recompile.
_______________________________________________________________________________________________
If you'd like more information on these as well as several other
window-managers, visit
this excellent
site, which has many links and screen shots.
_______________________________________________________________________________________________
Larry Ayers
Last modified: Fri Jan 24 19:11:42 CST 1997
_______________________________________________________________________________________________
Copyright &copy; 1997, Larry Ayers
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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_______________________________________________________________________________________________
SHELLS FOR THE END USER
by Larry Ayers
My first shell, though I didn't know it by that name, was
command.com in DOS. It couldn't do much more than simply execute
commands, but it served my needs at the time. Later on I discovered the
commercial DOS command.com replacement 4DOS, by JP Software. This came
as something of a revelation to this novice computer user. Suddenly I could
do file-name completion, use aliases, and change to a directory on a different
drive with simple keystrokes. Wow, I thought, how did those programmers at JP
Software think of so many clever command-line functions and options!
I later learned that 4Dos (and its OS/2 sibling, 4OS/2) were influenced and
inspired by the various shells used on unix systems. When I first began using
Linux I was able to learn the rudiments of the Bash shell fairly quickly
because of past experience with the JP Software products.
_______________________________________________________________________________________________
The ``Bourne-Again'' Shell
New users of Linux are encouraged (in part by distribution defaults) to
use the GNU Bash shell. Bash has been polished over the years to the point
that any remaining bugs probably affect only the skilled users who make use
of its more arcane functions. Bash, and its reduced-function alias
sh, work well as agents for executing shell scripts. As a command
shell in a console or an xterm Bash provides many labor-saving shortcuts and
functions, most of which beginning users don't use. Reading the voluminous
Bash documentation I began to realize that using Bash the way most users do,
i.e. as the default login and command shell, touches only a small fraction
of its capabilities. O'Reilly has published a three-hundred-page book
detailing Bash shell programming and usage !
Recently Chet Ramey, the maintainer of Bash, released version 2.00 to the
FTP sites. After reading the list of changes and bug-fixes I concluded that
advanced users will be more appreciative of the release than will common
end-users, like myself. It's an odd feeling to learn of a feature by finding
out that bugs have been fixed in it! The documentation for Bash is extensive;
the man pages are available now in HTML format (in a separate file called
bash-doc-2.0.tar.gz). Bash can be obtained both from Sunsite and its
mirrors (in /pub/gnu) and from the
main GNU site.
_______________________________________________________________________________________________
I remember the first time I navigated my way through the Slackware
installation menus; being offered the option to install tcsh and zsh made me
realize how little I knew. What were these alternative shells? Evidently
some users preferred them to bash, but why?
All of the shells discussed in this article are extensively documented, but
that very feature, as helpful as it is to advanced users, can make it
difficult to get a rough idea of why one shell might be preferable to another.
Luckily it isn't hard to install another shell just to try it out. Edit the
file /etc/shells (logged in as root) and add a line with the path to
the new shell. Then execute the command chsh; a default choice will be
offered to you. Ignore it and type in the name (with path) of the new shell.
You'll have to log out and log back in to activate the new shell.
_______________________________________________________________________________________________
Tcsh
In issue 12 of the Gazette Jesper
Pederson wrote a good introductory article about Tcsh; this article also
shows how Jesper's program Dotfile Generator can be used to help write
Tcsh resource files without spending many hours reading the manual. Since
that article appeared a new version of the Dotfile Generator has been released
which includes a module to generate Bash resource files. I highly
recommend this program, which is available from
this site. The Dotfile
Generator won't overwrite your existing files; it writes to another filename
(such as .bashrc-dotfile) This file can then be edited; I usually
transplant sections to my original files to try things out. The Dotfile
Generator allows you to try various features of your shell without having to
learn the precise rc-file syntax first.
1
A little resource-file editing will be necessary to change over to Tcsh.
The aliases which you have defined can be transplanted from your ~/.bashrc to
~/.cshrc without alteration, but the environment variables are another matter.
Bash (and other ``Bourne-compatible'' shells, such as Zsh) uses a different
format for this than Tcsh. As an example, export INFODIR=/mt/info in
the ~/.bash_profile would have to be changed to setenv INFODIR /mt/info
in ~/.tcshrc. I recommend going to the trouble of transferring aliases and
environment variables if you want to give Tcsh a try. If you don't you'll be
continually distracted by commands which don't work, and you will tend to
blame the shell.
The one feature which really stands out (if you're accustomed to Bash) is
the spelling-correction. When either a filename or command is misspelled the
shell pops up a suggested correction. If you tend to type commands quickly
and press ``enter'' without rereading what you've typed you'll love this.
Sometimes the shell is wrong, though, but pressing n rather than
y will force the shell to try and execute what you actually typed.
_______________________________________________________________________________________________
Zsh
After using Tcsh for a while, you may find yourself thinking, ``I really
don't want to switch completely to Tcsh; if only Bash had that spelling
correction built in!'' Zsh might be what you want.
Zsh is a Bourne-compatible shell like Bash but with several csh-like
features added. It also resembles the proprietary Korn shell as well as
Pdksh, a free Korn-shell clone. It's not at all difficult to adapt Bash
configuration files so that Zsh can use them as the syntax is nearly
identical. ~/.zshenv is analogous to ~/.bash_profile, while ~/.zshrc
corresponds to ~/.bashrc.
The first thing you notice when using Zsh for the first time is the prompt,
which by default looks like this:
<machine-name># /usr/local/src
As you can see, the current directory is on the right hand side of the
screen, giving more room for a command before the line breaks. When a typed
command reaches the path on the right the path disappears to make room.
The spelling correction behavior seems to be identical to that of Tcsh. As
with Bash and Tcsh, completion of paths and filenames is bound to the
tab key. Zsh has an elaborate implementation of programmable
completion, in which file-type specific behavior for completions can be set in
the resource-files.
One helpful aspect of Zsh's completion behavior deserves notice. Often
there will be a filename and a subdirectory with the same prefix, say if a
file called sample-2.01.tar.gz is unarchived into the directory in
which it resides, creating in the process a new subdirectory called
sample-2.01. Try the command cd sam<TAB> with some
shells and you will be asked if you want to change directory to
sample-2.01.tar.gz or to sample-2.01. Zsh is smart enough to
realize that directories don't normally have a tar.gz suffix, and
changes to the directory without comment or question.
The Zsh distribution contains extensive help-files which are in the
Info format, allowing them to be browsed from within Emacs or with a
stand-alone Info reader. After reading these documents I came away with
the impression that Zsh probably rivals Bash in the number of arcane features
and programming abilities. If you would like to see examples of the
complexity possible in Zsh configuration, take a look at The Next
Level, a package of Linux configuration files with explanation which has
become a part of recent Red Hat distributions. The Next Level's author,
Greg J. Badros, has included an elaborate set of Zsh resource files.
I found them to be quite informative as an example of what's possible with
this shell.
Zsh seems to be under active development; version 3.00 was released last
year, and there have been minor releases since then. There is a Zsh
home-page here which can serve as a good
introduction.
_______________________________________________________________________________________________
CONCLUSION
These shells certainly aren't hard to find; most distributions I've seen
include preconfigured packages for all three of them. One caveat: if you
decide to settle on Tcsh or Zsh as your login shell don't remove Bash, or its
symlink /bin/sh. Many shell scripts rely on /bin/sh in order to
run properly. Some packages, such as the Andrew User Interface System, like
to have csh available, so if you have the disk-space Tcsh, along with
its symlink /bin/csh may as well be retained even if it's not your
login shell.
The choice of shells reminds me of the eternal debate between vi-users and
emacs-users. A decision depends more on working-style and personality than
logic; try them all and see which one fits!
_______________________________________________________________________________________________
Larry
Ayers
Last modified: Fri Jan 24 23:34:09 CST 1997
_______________________________________________________________________________________________
Copyright &copy; 1997, Larry Ayers
Published in Issue 14 of the Linux Gazette
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_______________________________________________________________________________________________
Novice Bash Tip -- Edit command-lines "joe-style"
By Joel Wilf, av293@lafn.org
_______________________________________________________________________________________________
If like me, you come from the world of DOS and WordStar, you
feel right at home with the joe editor, which uses WordStar
keystrokes.
But as soon as you exit joe, you're back in the land of bash,
where command-lines are edited "emacs-style." Soon,
your fingers are confused. Before you know it, you're pressing
<control>-d to move the cursor, only to find your command-line
disappearing.
But why use one set of keys to edit text and another to edit
commands? The beauty of Linux is that you can customize it to
your heart's content. Here's how to make bash act like our old
friend, joe:
STEP 1: DEFINE KEYS WITH .INPUTRC:
The bash command-line is handled by the GNU readline library. So
it's not surprising that bash uses the same keystrokes as GNU
emacs. Luckily, you can change these key-bindings simply by
setting new values in the file .inputrc.
The first step is to go to your $HOME directory and open or
create a text file named .inputrc. Then add the following
lines, which tell bash to use the basic joe keystrokes:
"\C-d": forward-char "\C-s": backward-char "\C-f": forward-word "\C-a": backward-word "\C-g":
delete-char "\C-t": kill-word "\C-y": kill-whole-line
You can also add the following lines, which fix the behavior of
the <home>, <end>, <delete>, and <backspace>
keys:
"\e[1~": beginning-of-line "\e[3~": delete-char "\e[4~": end-of-line DEL: backward-delete-char
Finally, you can use .inputrc to modify any one of the dozens of
keystrokes and variables that control bash. (Among other
things, you can get bash to stop beeping at you!) Check the
READLINE section of the bash man page for details.
STEP 2: FIX TERMINAL SETTINGS WITH STTY:
An experienced Linuxer will see that the changes we made to
.inputrc has created a problem. We set <control>-s to
it's WordStar meaning. But the Linux terminal uses
<control>-s to send the "stop" signal.
Pressing <control>-s freezes the terminal until you type
<control>-q, the "start" signal.
The easiest way to fix this is to tell the terminal to use a
different "stop" key. To reassign "stop" to
<control>-p, type the following line (and put it in your
.bashrc to make it permanent):
stty stop '^p'
You can prove this works by pressing <control>-p then
<control>-q. It's also a good idea to check your terminal
configuration -- especially if you change other keys with
.inputrc. Type:
stty -a
This will display your terminal settings. If you reassigned the
"stop" key as shown above, you should see "stop = ^P".
Now you're home free. All you have to do is exit and log in
again. And you can edit commands "joe-style."
_______________________________________________________________________________________________
Copyright &copy; 1997, Joel Wilf
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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_______________________________________________________________________________________________
Pick an Editor, Any Editor
By Jens Wessling, jwesslin@erim.org
_______________________________________________________________________________________________
[IMAGE]
im (VI iMproved)
_______________________________________________________________________________________________
One day I realized that I seem to spend an
inordinate amount of time in front of a computer screen
and more precisely with a text editor in front of me.
This should hardly have been a surprise to me considering
I work with computers for eight to ten hours a day and then
I go home and spend several more. I guess that this obvious
fact finally struck home with me. I would guess I spend
about 20-30 hours a week in a text editor alone. With some
quick calculations I realized that this adds up to over 1000
hours a year. That is over 40 solid days of my life every
year in an editor. (That is a conservative estimate.) This
realization spurred me to try to optimize the time I spend
in my editor.
The first step I took was to try and find the best
editor around. I started asking around to see who used
what and to try to find out what the important qualities
of an editor were. Don't make this mistake.
Editors are one of the most religious beliefs a programmer
holds. Every programmer is convinced that there's is the
best. My office-mate uses PICO, some of my co-workers use
EMACS, VI, SlickEdit, or any one of an unending list. Every
person I talked to insured me that their selection was by
far the best. When I inquired about the differences, they
were primarily insignificant. That was when I learned the
horrible truth. Most editors are essentially equivalent.
No matter how hard people insist, most editors have more
features than any user will ever use. (Except PICO). In the
Linux community, these selections basically fall in to one
of two categories. VI clones, or Emacs. My recommendation
is that everyone learn one of these well. It doesn't really
matter which one, just pick one, stick with it and use it.
(Religiously if you must.)
I have gone to great lengths to learn VIM, a VI clone. And
certainly if not THE best, one of the top contenders. Many
features are shared among VI clones, basically the VI subset.
The additional features are basically individual to each
clone. VIM comes with most, if not all, Linux distributions.
The home page for VIM is
http://www.math.fu-berlin.de/~guckes/vim/. VIM is in
active development and is getting better by the day. Syntax
highlighting should be out, if not by the time you read this,
then soon thereafter.
I will assume that most people know the basics of VI and want
to change it from a simple tool to a powerful one. I will share
some of the handy tips and tricks I use.
Programming, Tabs, and Tags.
ctags is a marvelous utility for C and C++ Programmers. ctags
comes with the VIM distribution. What this utility does is
create a list of all the subroutine names in the files you
specify and allow you to jump to the given subroutine while
in you editor with just one keypress. The way you run ctags
is simple.
ctags *.c or ctags *.cpp
Then, crank up your editor and move to wherever it is you
call any subroutine from and press [CTRL]-]. This will
take you immediately to wherever the routine is, even if
it is in a different file.
File Switching
I frequently work with several files concurrently and I
need to switch between these files continually. The
command to switch to another file in VIM is ":e fn".
The shortcut to switch to the last file edited is ":e #".
This is fine for normal use, but I switch files often, and
4 keystrokes seems like a bit much. This is where VIM's
key mapping comes in. VIM like most editors has an rc
file. It is called .vimrc, what a shock. 8)
In this file I have the following command.
" Save and switch to other buffer. map N :w [CTRL]-M
This command lets me switch buffers with a single keypress.
The other nice feature in VIM for switching between files
is tab completion for file names. The way tab completion
works is to take whatever letters you have typed in so
far on for the file name and find all of the files that
could possibly match. Hitting tab will scroll through
the list of files until you find the one you want. If no
beginning letters are specified for the file name, it will
scroll through them all.
Mapping
I do a LOT of coding and I find that I often need to comment
out blocks of lines. I have developed 2 macros for handling
this with a minimum of effort.
map C 0i/*[CTRL-ESC]A*/[CTRL-ESC]j map T 0xx$xxj
If you examine the first line, you will see that it does the
following.
* Moves to the beginning of the line
* Enters Insert Mode
* Places "\*" there
* Escapes to command mode
* Adds "*/" to the end of the line
* Escapes to command mode
* Moves down One line
The second line does the following.
* Moves to the beginning of the line
* Removes 2 characters
* Moves to the end of the line
* Removes 2 characters
* Moves down One line
I can type "12C" in command mode and it will comment out the
next dozen lines. and "12T" will uncomment a dozen lines that
were commented by "C".
Keep in mind that when you remap keys, they lose there original
values. In this case, "C" was an odd Delete until end of line
and next several lines into a given buffer, and "T" was a command
I can't really figure out from the documentation. I don't really
miss these two but be careful that you don't map "i" or "x" or
anything else you might need later.
Have fun with this. I hope to have more later.
jEnS Wessling
_______________________________________________________________________________________________
Copyright &copy; 1997, Jens Wessling
Published in Issue 14 of the Linux Gazette
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_______________________________________________________________________________________________
A PHILOSOPHY FOR CHANGE FROM DOS TO LINUX
By R. Frank Louden flouden@netusa1.net
_______________________________________________________________________________________________
Unavoidable Confusion
On the surface, changing from a MS DOS/MS Windows user to a Linux user
is not such a major change. After all, to change directories in
Linux, you use the ``cd'' command and that is the same as DOS. Linux
provides X windows as a GUI and there are a number of similarities
with MS Windows.
So maybe all that is necessary is to learn a few different commands
and you are off and running. Well, right and wrong.
You might find yourself in the situation I was in when I first decided
to install Linux. I had never had any experience with Unix or Linux or
much of anything else outside of the realm of Microsoft.
The Intel/Microsoft consortium had given me a false sense of command
over my PC. I had no idea of the ``behind the scenes'' activity that
went on when DOS booted and Windows came up with it's attractive
colors and cute little icons. I began to learn a bit when I tried to
setup some software that wasn't MS applications. At work I learned
that it was necessary to occasionally contact an equipment
manufacturer to get the appropriate drivers for MS Windows. But
all-in-all I was successful in almost every attempt. Little did I
know...
_______________________________________________________________________________________________
Fools Rush IN...
As you may have deduced, I work with computers and less obvious (but
it'll get even less obvious as we go along, I'm sure!) I have some
schooling in the computer field. So it won't be too surprising to
find that I was beginning to feel somewhat stifled by the MS environment.
I knew there were more colors, more sounds, more ways of
doing things than I saw on the shelf (at a rather high $$ amount, I
might add) in my local computer store and in the pages of my favorite
computer magazines.
One day, a friend mentioned Linux to me. She was quite an Internet
fan. She spent hours in IRC channels and had heard about some of the
Unix applications from the I-net dinosaurs (Unix users). So one day,
while browsing through the computer books shelves at my favorite
bookseller's, I noticed a copy of ``Linux Unleashed'' published by Sam's
Publishing. I bought it thinking I'd just see what all the fuss was
about.
_______________________________________________________________________________________________
Time Wounds All Heels
I couldn't wait. When I opened the pages and began reading I was
intrigued. The complexity and yet the continuous assurances that it
*could* be done had me all fired up to try out this ``experimental'' OS.
Lucky me! A CD was glued inside the back cover of the book. My
problem was, all I owned was a 386SX with 2 MB of memory and a 65 MB
hard-drive. Not enough! So I bought a new PC.
I ordered a Micron with 16 MB of memory and a 1.6 GB hard drive and a
CD-ROM drive. A heck of a lot of machine to my way of thinking! When
it arrived, it came pre-loaded with MS Win95 (doesn't everything?)
I decided to use FIPS to do a ``non-destructive'' repartition of my new
hard-drive. Well, it worked but the problem is the FIPS program took
every bit of empty space on the drive, I couldn't write a single file
in Win95 and I wasn't ready to completely forsake my old OS. So,
having already made a backup (yeah, right!) I did a complete reformat
of my C drive. I split the drive into 4 logical partitions and saved
one of them for Linux exclusively.
Even for someone with a fair amount of PC experience, there is room
for mistakes, doing what I was doing, and I made 'em. One thing I
didn't do (I didn't know about this at the time) was to also create a
small partition to use as Linux swap space. I did this a couple of
months later when I re-installed to upgrade to Slackware 3.1.
So here is a warning...
IF YOU JUST GOT THAT PC FOR CHRISTMAS AND YOU'VE NOT EVER SET ONE UP BEFORE AND YOU ARE
JUST LEARNING MS WINDOWS -- DO NOT INSTALL LINUX! DON'T EVEN THINK ABOUT IT!
Take your time and learn about that machine and the wondrous things
it is capable of doing for you. If later (and probably MUCH later)
you find it is boring doing the Microsoft Word cut-and-paste shuffle,
and Doom starts putting you to sleep, and you've invested in a class
or two in Computer Science at your local community college, Linux
might be just the thing.
_______________________________________________________________________________________________
A Coincidence?
While I was typing away on this article, the phone rang. It was my
friend Ben and he had just hooked up his brand new P166 last
evening. First thing he said was, ``I got this new computer last night
and I need help before I throw it out the window.'' I got up and drove
over to his place. (Coldest day of the year so far! Brrrrr!) I looked
at his machine. Pre-loaded with Win95 (aren't they all?) He didn't
know what to do once the system booted and displayed the new GUI. I
showed him a couple of things and then told him not to install
Linux. He's definitely not ready!
_______________________________________________________________________________________________
Who Is Ready?
None of us who are migrating from MS dominance. It's that simple.
But don't let that discourage you. If you know a bit more about PCs
than the occasional, at work, or gaming user and if you are as
fascinated by computing concepts and advances (Java, SMP, Graphics
rendering, etc.) as I am. If you LIKE to program or if you want to
set up as an ISP, then Linux is for you. And be prepared, Linux is a
whole different animal!
_______________________________________________________________________________________________
Time Heals All Wounds
Learning takes time and in time you will learn. I started with Linux
in March of 1996. In the last ten months, I have installed Linux
(Slackware at home and Debian at work) about eight times. I have
learned something every day. I will say that while Linux is priced
right, I have spent more on books in the last ten months than I had in
the last 5 years.
Here are some of the things I have accomplished...
I have setup...
* PPP Link to my ISP
* X11R6
* GNAT Ada Compiler
* TkDesk
* TclTutor
* TkMan
* Netscape
* Mosaic
I am learning...
* GNU C/C++
* Perl
* Tcl/Tk
* Pov-Ray
* HTML Document Design
And there are many, many other places to go.
Let me say that ``setup'' is not truly the best word to use. In many
instances the setups I mentioned above required only that I tweak a
configuration file or adjust a Makefile. In some instances the program
refused to work and I had to read and study and yes, I had to ask a
couple of questions from the newsgroups too.
Out of the box, my printer didn't function so I had to read the
Printing HOWTO. Of course, it might have worked but how would I know
since I didn't have any idea about how lpr was used to queue up a
print job. Then I needed to get a SLIP or PPP connection functioning
so I could ask those questions on the newsgroups. I had been taught
some Ada when in school and when I saw GNAT was available, I wanted to
have it so I might refresh my skills there. I had to wait for
InfoMagic's September ``Linux Developer's Resource'' before I was able
to get a GNAT installed that would compile anything.
Just last week I got Pov-Ray up and running and I have been
enthusiastic about ray-traced images since I first saw a ringed
planet scene created with it. But I had to wait...and tinker...and
wait...and read...and make mistakes...and start all over again. There
are times when, like my friend Ben, I feel like throwing the PC out the
window and I have learned to move on to something else. And whenever
I move on, I learn more.
_______________________________________________________________________________________________
Linux Yes!
So I am sold! I have not as yet taken the MS partitions off of my
machine but 95% of the time I am working within the Linux
environment. Although sometimes my frustrations run high, I can
honestly say that I have not had as much fun with a computer since I
first started my Pascal classes back a few years ago.
So here I am, somewhere between a novice and a guru, lost in the Linux
OS Wonderland. I'm having a great time...why don't you join me?
_______________________________________________________________________________________________
Copyright &copy; 1997, R. Frank Louden
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
Procmail Mini-Tutorial:
AUTOMATED MAIL HANDLING
by
Jim Dennis, Proprietor,
Starshine Technical Services
Converted to HTML by
Heather Stern
_______________________________________________________________________________________________
procmail is the mail processing utility language
written by
Stephen van den Berg
of Germany. This article provides a bit of background for
the intermediate Unix user on how to use procmail.
As a "little" language (to use the academic term)
procmail lacks many of the features and constructs
of traditional, general-purpose languages. It has
no "while" or "for" loops. However it "knows"
a lot about Unix mail delivery conventions and
file/directory permissions -- and in particular
about file locking.
Although it is possible to write a custom mail
filtering script in any programming language
using the facilities installed on most Unix
systems -- we'll show that procmail is the tool
of choice among sysadmins and advanced Unix
users.
Unix mail systems consist of MTA's (mail
transport agents like sendmail, smail, qmail
mmdf etc), MDA's (delivery agents like
sendmail, deliver, and procmail), and MUA's
(user agents like elm, pine, /bin/mail, mh,
Eudora, and Pegasus).
On most Unix systems on the Internet sendmail
is used as an integrated transport and delivery
agent. sendmail and compatible MTA's have the
ability to dispatch mail *through* a
custom filter or program through either of
two mechanisms: aliases and .forwards.
The aliases mechanism uses a single file
(usually /etc/aliases or /usr/lib/aliases)
to redirect mail. This file is owned and
maintained by the system administrator.
Therefore you (as a user) can't modify it.
The ".forward" mechanism is decentralized.
Each user on a system can create a file
in their home directory named .forward
and consisting of an address, a filename,
or a program (filter). Usually the file
*must* be owned by the user or root and
*must not* be "writeable" by other users
(good versions of sendmail check these factors
for security reasons).
It's also possible, with some versions of
sendmail, for you to specify multiple addresses,
programs, or files, separated with commas. However
we'll skip the details of that.
You could forward your mail through any
arbitrary program with a .forward that consisted
of a line like:
"|$HOME/bin/your.program -and some arguments"
Note the quotes and the "pipe" character. They are
required.
"Your.program" could be a Bourne shell script,
an awk or perl script, a compiled C program or
any other sort of filter you wanted to write.
However "your.program" would have to be written to
handle a plethora of details about how sendmail would
pass the messages (headers and body) to it, how you would
return values to sendmail, how you'd handle file locking
(in case mail came in while "your.program" was still
processing one, etc).
That's what procmail gives us.
What I've discussed so far is the general information
that applies to all sendmail compatible MTA/MDA's.
So, to ensure that mail is passed to procmail for
processing the first step is to create the .forward
file. (This is safe to do before you do any configuration
of procmail itself -- assuming that the package's binaries
are installed). Here's the canonical example, pasted from
the procmail man pages:
"|IFS=' '&&exec /usr/local/bin/procmail -f-||exit 75 #YOUR_USERNAME"
This seems awfully complicated compared to my
earlier example. That's because my example was
flawed for simplicity's sake.
What this mess means to sendmail (paraphrasing into
English) is:
* Pipe the mail to the following command(s):
* Set the shell's "inter-field seperator" (IFS) to a space, and -- if that went O.K. (&&)
execute the program named "/usr/local/bin/procmail"
(yours may need to be different -- try the command 'which procmail' to see if it's on
the path or 'locate procmail' if your system maintains a file locator database).
* The procmail program is being passed a set of switches: "-f-" which tells it to "update
timestamp in the leading the 'From' line in the header"
(this last bit is rather obscure and has to do with how messages are normally stored in
your "incoming" or mail file or "spool" as we Unix hacks like to call it).
* The next part of this .forward command is the Bourne shell's "||" operator which is
basically a continuation from the "and" (&&) operator that we used before. It says "or"
(if that command didn't work -- i.e. it returned any error) then "exit" (stop
processing) and return an error number 75 (which we presume is meaningful to sendmail
-- the program that called this command).
* The last part of this .forward expression is a comment which according to the man
pages:
"is not actually a parameter that is required by procmail, in fact, it will be discarded
by sh before procmail ever sees it; it is however a necessary kludge against
overoptimising sendmail programs:"
* You should just change the phrase YOUR_NAME to your login name on that system.
This complicated line can be just pasted into most
.forward files, minimally edited and forgotten.
If you did this and nothing else your mail would
basically be unaffected. procmail would just
look for its default recipe file (.procmailrc) and
finding none -- it would perform its default action
on each messages. In other words it would append new
messages into your normal spool file.
If your ISP uses procmail as its local delivery
agent then you can skip the whole part of about
using the .forward file -- or you can use it anyway.
In either event the next step to automating your
mail handling is to create a .procmailrc file in
your home directory. You could actually call
this file anything you wanted -- but then you'd
have to slip the name explicitly into the .forward
file (right before the "||" operator). Almost
everyone just uses the default.
Now we can get to a specific example. So far all
we've talked about it how everything gets routed
to procmail -- which mostly involves sendmail and
the Bourne shell's syntax. Almost all sendmail's
are configured to use /bin/sh (the Bourne shell)
to interpret alias and .forward "pipes."
So, here's a very simple .procmailrc file:
:0c:
$HOME/mail.backup
This just appends an extra copy of all incoming
mail to a file named "mail.backup" in your
home directory.
Note that a bunch of environment variables are preset
for you. It's been suggested that you should
explicity set SHELL=/bin/sh (or the closest
derivative to Bourne Shell available on your system).
I've never had to worry about that since the shells
I use on most systems are already Bourne compatible.
However, csh and other shell users should take note
that all of the procmail recipe examples that I've
ever seen use Bourne syntax.
The :0 line marks the beginning of a "recipe"
(procedure, clause, whatever. :0 can be followed
be any of a number of "flags." There is a literally
dizzying number of ways to combine these flags. The
one flag we're using in this example is 'c' for
"copy."
You might ask why the recipe starts with a :0.
Historically you used to use :x (where x was a
number). This was a hint to procmail that the
next x lines were conditions for this recipe. Later,
the option was added to precede conditions with a
leading asterisk -- so they didn't have to be manually
counted. :0 then came to mean something like:
"count them yourself."
The second colon on this line marks the end of
the flags and the beginning of the name for a
lockfile. Since no name is given procmail will
pick one automatically.
This bit is a little complicated. Mail might arrive
in bursts. If a new message arrives while your script
is still busy processing the last message -- you'll
have multiple sendmail processes. Each will be dealing
with one message. This isn't a problem by itself.
However -- if the two processes might try to write
into one file at the same time they are likely to
get jumbled in unpredictable ways (the result will
not be a properly formatted mail folder).
So we hint to procmail that it will need the check
for and create a lockfile. In this particular case
we don't care what the name of the lock file would
be (since we're not going to have *other* programs
writing into the backup file). So we leave the
last field (after the colon) blank. procmail will
then select its own lockfile name.
If we leave the : off of the recipe header line
(ommitting the last field entirely) then no lockfile
is used.
This is appropriate whenever we intend to only
read from the files in the recipe -- or in cases
where we intend to only write short, single line
entries to a file in no particular order (like
log file entries).
The way procmail works is:
It receives a single message from sendmail
(or some sendmail compatible MTA/MDA). There
may be several procmail processing running
currently since new messages may be coming
in faster than they are being processed.
It opens its recipe file (.procmailrc by default
or specified on its command line) and parses
each recipe from the first to the last
until a message has been "delivered" (or
"disposed of" as the case may be).
Any recipe can be a "disposition" or "delivery"
of the message. As soon as a message is
"delivered" then procmail closes its files, removes
its locks and exits.
If procmail reaches the end of it's rc file
(and thus all of the INCLUDE'd files) without
"disposing" of the message -- than the message
is appended to your spool file (which looks
like a normal delivery to you and all of your
"mail user agents" like Eudora, elm, etc).
This explains why procmail is so forgiving
if you have *no* .procmailrc. It simply
delivers your message to the spool because
it has reached the end of all its recipes
(there were none).
The 'c' flag causes a recipe to work on a "copy"
of the message -- meaning that any actions
taken by that recipe are not considered to be
"dispositions" of the message.
Without the 'c' flag this recipe would catch
all incoming messages, and all your mail would
end up in mail.backup. None of it would get
into your spool file and none of the other recipes
would be parsed.
The next line in this sample recipe is simply
a filename. Like sendmail's aliases and .forward
files -- procmail recognizes three sorts of
disposition to any message. You can append it
to a file, forward it to some other mail address,
or filter it through a program.
Actually there is one special form of "delivery"
or "disposition" that procmail handles. If you
provide it with a directory name (rather than a
filename) it will add the message to that directory
as a separate file. The name of that file will be
based on several rather complicated factors that
you don't have to worry about unless you use
the Rand MH system, or some other relatively
obscure and "exotic" mail agent.
A procmail recipe generally consists of three
parts -- a start line (:0 with some flags) some
conditions (lines starting with a '*' -- asterisk --
character) and one "delivery" line which can be
file/directory name or a line starting with a '!' --
bang -- character or a '|' -- pipe character.
Here's another example:
:0
* ^From.*someone.i.dont.like@somewhere.org
/dev/null
This is a simple one consisting of no flags,
one condition and a simple file delivery. It simply
throws away any mail from "someone I don't like."
(/dev/null under Unix is a "bit bucket" -- a bottomless
well for tossing unwanted output DOS has a similar
concept but it's not nearly as handy).
Here's a more complex one:
:0
* !^FROM_DAEMON
* !^FROM_MAILER
* !^X-Loop: myaddress@myhost.mydomain.org
| $HOME/bin/my.script
This consists of a set of negative conditions (notice
that the conditions all start with the '!' character).
This means: for any mail that didn't come from a
"daemon" (some automated process) and didn't come
a "mailer" (some other automated process) and which
doesn't contain any header line of the form:
"X-Loop: myadd..." send it through the script in
my bin directory.
I can put the script directly in the rc file
(which is what most procmail users do most of the
time). This script might do anything to the mail.
In this case -- whatever it does had better be good
because procmail way will consider any such mail
to be delivered and any recipes after this will
only be reached by mail from DAEMONs, MAILERs
and any mail with that particular X-Loop: line
in the header.
These two particular FROM_ conditions are actually
"special." They are preset by procmail and actually
refer to a couple of rather complicated regular
expressions that are tailored to match the sorts of
things that are found in the headers of most mail
from daemons and mailers.
The X-Loop: line is a normal procmail condition.
In the RFC822 document (which defines what e-mail
headers should look like on the Internet) any line
started with X- is a "custom" header. This means
that any mail program that wants to can add pretty
much any X- line it wants.
A common procmail idiom is to add an X-Loop: line
to the header of any message that we send out --
and to check for our own X-Loop: line before
sending out anything. This is to protect against
"mail loops" -- situations where our mail gets
forwarded or "bounced" back to us and we endlessly
respond to it.
So, here's a detailed example of how to
use procmail to automatically respond to mail
from a particular person. We start with
the recipe header.
:0
... then we add our one condition (that the mail
appears to be from the person in question):
* ^FROMharasser@spamhome.com
FROM is a "magic" value for procmail -- it checks
from, resent-by, and similar header lines. You could
also use ^From: -- which would only match the header
line(s) that start with the string "From:"
The ^ (hiccup or, more technically "caret")
is a "regular expression anchor" (a techie phrase that
means "it specifies *where* the pattern must be
found in order to match." There is a whole book
on regular expression (O'Reilly & Associates).
"regexes" permeate many Unix utilities, scripting
languages, and other programs. There are slight
differences in "regex" syntax for each application.
However the man page for 'grep' or 'egrep' is an
excellent place to learn more.
In this case the hiccup means that the pattern
must occur at the beginning of a line (which is
its usual meaning in grep, ed/sed, awk, and other
contexts).
... and we add a couple of conditions to avoid
looping and to avoid responding to automated systems
* !^FROM_DAEMON
* !^FROM_MAILER
(These are a couple more "magic" values.
The man pages show the exact regexes that are
assigned to these keywords -- if you're curious or
need to tweak a special condition that is
similar to one or the other of these).
... and one more to prevent some tricky loop:
* !^X-Loop: myaddress@myhost.mydomain.org
(All of these patterns start with "bangs" (exclammation
points) because the condition is that *no* line of the
header start with any of these patterns. The 'bang' in
this case (and most other regex contexts) "negates" or
"reverses" the meaning of the pattern).
... now we add a "disposition" -- the autoresponse.
| (formail -rk \
-A "X-Loop: yourname@youraddress.com" \
-A "Precendence: junk"; \
echo "Please don't send me any more mail";\
echo "This is an automated response";\
echo "I'll never see your message";\
echo "So, GO AWAY" ) | $SENDMAIL -t -oi
This is pretty complicated -- but here's how it works:
* The pipe character tells procmail that it should launch a program and feed the message
to it.
* The open parenthesis is a Bourne shell construct that groups a set of commands in such
a way as to combine the output from all of them into one "stream." We'll explain this
more later.
* The 'formail' command is a handy program that is included with the procmail package. It
"formats" mail headers according to its command line switches and its input.
+ -rk tells 'formail' to format a "reply" and to "keep" the message body. With these
switches formail expects a header and body as input.
+ The -A parameters tells formail to "add" the next parameter as a header line. The
parameters provided to the -A switch must be enclosed in quotes so the shell
treats the whole string (spaces and all) as single parameters.
+ The backslashes at the end of each line tell procmail mail to treat the next line
as part of this one. So, all of the lines ending in backslashes are passed to the
shell as one long line.
+ This "trailing backslash" or "line continuation" character is a common Unix idiom
found in a number of programming languages and configuration file formats.
+ The semicolons tell the shell to execute another command -- they allow several
commands to be issued on the same command line.
+ Each of the echo commands should be reasonably self-explanatory. We could have
used a 'cat' command and put our text into a file if we wanted. We can also call
other programs here -- like 'fortune' or 'date' and their output would be combined
with the rest of this).
+ Now we get to the closing parenthesis. This marks the end of the block of commands
that we combined. The output from all of those is fed into the next pipe -- which
starts the local copy of sendmail (note that this is another variable that
procmail toughtfully presets for us).
+ The -t switch on sendmail tell it to take the "To:" address from the header of
it's input (where 'formail -r' put it) and the -oi switch enables the sendmail
"option" to "ignore" lines that consist only of a 'dot' (don't worry about the
details on that).
Most of the difficulty in understanding procmail
as nothing to do with procmail itself. The intricacies
of regular expressions (those wierd things on the
'*' -- conditional lines) and shell quoting and
command syntax, and how to format a reply header that
will be acceptable to sendmail (the 'formail' and
'sendmail' stuff) are the parts that require so
much explanation.
The best info on mailbots that I've found used to be
maintained by Nancy McGough (sp??) at the Infinite Ink
web pages:
http://www.jazzie.com/ii/
More information about procmail can be found in
Era Eriksson's "Mini-FAQ." at
http://www.iki.fi/~era/procmail/mini-faq.html
I also have a few procmail and SmartList links off of
my own web
pages.
_______________________________________________________________________________________________
Copyright &copy; 1997, James T. Dennis
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
USR
Utilizing the US Robotics Pilot with Linux
by James McDuffie,mcduffie@scsn.net
_______________________________________________________________________________________________
Why the Pilot?
There are a lot of Personal Digital Assistants available on the market
these days. These include the Newton, Windows CE machines, and Psion. But
the PDA being discussed here is the US Robotics Pilot. Before purchasing a
PDA I thought carefully about a number of issues. These included cost,
portability, and how well it could be expanded.
The are a couple reasons why I purchased the Pilot. For one thing the
Pilot is not very expensive. The Pilot comes in two different versions,
called the Pilot 1000 and the Pilot 5000. These are the exact same except
for the amount of memory they have loaded. The Pilot 1000 has 128k of
memory while the Pilot 5000 has 512k of memory. What I did was purchase a
Pilot 1000 and a 1 MB upgrade chip at the same time. This way I saved
money in the long run than if I had purchased a Pilot 5000 and then later
upgraded to 1 MBB of memory. The Pilot is considerably cheaper than other
PDAs. Such as the Newton which is priced as under $800. The Pilot 1000
can be found for as low as $224 and the Pilot 5000 for as low as $269.
The 1 MB upgrade chip can be found for as little as $89. Prices such as
this make the Pilot a cost effective solution.
Another issue was how portable the Pilot is. Carrying around a heavy PDA
all day is not very comfortable. But the Pilot is very portable. It
measures 4.7 x 3.2 x .7 inches, small enough to fit comfortably in your
hand. The Pilot only weighs 5.7 ounces, with batteries. Because of this
the Pilot can fit comfortably in your shirt pocket or your pants pocket.
The Pilot's power supply is two 2 triple A batteries. These batteries can
last you up to a month if you use the Pilot moderately. After all a PDA is
supposed to help you, not burden you down by being bulky and heavy.
The Pilot is very expandable too. Such is the case with the 1 MB
upgrade chip that can be purchased from varies places. I find that 1 MB
of memory is more than enough memory for my needs. The Pilot is also
expandable in that you can upload any of numerous shareware or commercial
applications for the Pilot. There is even a program that allows you to
hook your Pilot up to a modem and dial into your ISP and then check your
POP mail! These applications are very small. The average application
made for the Pilot runs about 10k. With a 1 MB chip you could
theoretically have 100 10k apps on the Pilot. The Pilot features a RS-232
serial connector on the bottom of it. The connector is used for syncing
the Pilot with your desktop computer or for other uses. Other uses
include hooking up a modem or hooking up a soon to be release wireless
modem and pager. The Pilot can grow as your need for it grows.
_______________________________________________________________________________________________
Using the Pilot with Linux
Right now there is software available for use with the Pilot and Linux and
other Unix flavors. You can obtain the software for use with Linux
from:
ftp://ns1.pfnet.com/pub/PalmOS/
This software is still in development, but is highly usable. To use this
software all you have to do is get the latest pilot-link package and
untar/ungzip it. Once you have it expanded all it takes is to run the
configure script and then do a make. You will then have
about 16 programs depending on what version you have. I suggest that you
install all of these programs into their own directory. I have mine
installed in /usr/local/pilot and have included this directory in my path
statement. This will make it easier for you to play around with the
software. If you want to run the software as any user other than root,
you will have to set them suid root. I have done this but restricted
their execution to a group that only my login is a member of. This allows
the software to execute the serial port.
The software is simple enough to use. You simply supply supply the program
name, the serial port and other information such as a filename. The
pilot-xfer program allows you to install programs or data files that
programs use into the Pilot. To install program all you would have to do
is use the command pilot-xfer /dev/cua?? -i [program name]. After
entering this your press the hot-sync button on the Pilot cradle and the
Pilot installs the program. The program is then available for immediate
use. Or if you wanted to install a text file into the memo you would
simply enter install-memo /dev/cua?? [file name]. There are plenty
of other programs that help you transfer information with other
applications such as the date book, the address book and the to do list.
For me, the name of these programs are pretty long and with typing the
serial device name it gets tedious fast. So I set up a couple of aliases
to speed up things. Some of my aliases are:
alias pxi='pilot-xfer /dev/cua2 -i'
alias im='install-memo /dev/cua2'
These are the functions I use the most, because I hardly ever download
applications from my Pilot since I already have them on my hard drive.
The same goes for memos I install. But for the information that I create
in the Pilot I use the sync-memodir program. It puts every memo in
a separate fill. But the down side is that does not put the files in
categories as they are on your Pilot. The up side is that the Windows
software is not required.
_______________________________________________________________________________________________
What to do if you do not have a free serial port
One problem I encountered was that I did not have a free serial port. My
mouse is on cua0 and my modem on cua1. For a while I had to switch the
Pilot cradle with my modem. This was highly annoying because I could not
use the modem while I was playing with my Pilot. I solved this with a $29
dollar ISA card I found at a local computer story, local as in locally
owned and operated. The card is called the COM-5 card and is manufactured
by Mouse Systems.
The card is useful because if COM1 and COM2 are in use then COM3 and COM4
are not available. A COM port is simply a label that identifies a
specific IRQ and address. COM1 and COM3 share the same IRQ as does COM2
and COM4. But this card allows you to add another serial port at any
combination of IRQ and address that you desire. I have mine set on IRQ 12
and address 238. To get this to work with Linux all I had to do was tell
Linux to map this specific address and IRQ combination to the device
/dev/cua2. The following command does this:
setserial /dev/cua2 port 0x238 irq 12 autoconfig
It tell Linux where the serial port is available and to what device to
map it. With this working I was able to play around with my Pilot while
using my modem. Also I now have an extra serial port should I need it for
other tasks.
_______________________________________________________________________________________________
Logging in to a Linux computer via the Pilot
Logging into a Linux computer via the Pilot is possible. It is not really
that hard once you have the correct software. All you need is the
application called Simple Term which can be obtained from Adam's Software
Archive listed in the links section. Install the software on the Pilot
and then make sure the Pilot is hooked up to the serial port. Run agetty
on the serial device such as with this command:
/sbin/agetty 19200 cua2 vt100
And then put the Pilot in the cradle and hit online. You should then be
able to talk with your Linux computer. The reason this works with the
cradle is because the cradle is basically just a null modem hook up to
the computer. Because of this a null modem adapter put on the cradle will
allow you to use the Pilot on a modem, because of the fact that it
reverses the null modem feature of the cradle. Logging into your Linux
computer via the Pilot is not the most useful thing in the world since
the program does not contain any terminal emulation. But it is possible
which makes it fun.
_______________________________________________________________________________________________
Links
US Robotics Pilot Page
Scott's Pilot Page
Adam's USR Pilot Software Archive
Aslan's Pilot PDA Links
These links should be enough to learn about the US Robotics Pilot and how
to use them. I hope this information will be helpful. If you have any
questions what so ever, please contact me.
_______________________________________________________________________________________________
Pilot-Unix Mailing List
The pilot-unix mailing list is for discussion and idea-sharing for those
interested in using the US Robotics Pilot PDAs with UNIX systems. This
includes people who are interested in helping to develop tools to allow the
Pilot to operate with UNIX, and possibly to develop an SDK for the Pilot
for Unix.
All postings to the list should be sent to the address
pilot-unix@lists.best.com
Commands, such as subscribe or unsubscribe requests should be sent to the
address
pilot-unix-request@lists.best.com
Note that there are two list modes - normal (you receive each message as it
is sent) and digest. The default mode is digest mode. To subscribe to the
digest, send an email message with the single word "subscribe" in the
message body to "pilot-unix-request@lists.best.com". To subscribe to the
normal list, use the word "subsingle" in the message body. You can also get
a list of commands which the list server understands by sending mail with
the single word "help" in the body to the -request address.
If you have administrative questions or requests which require the
intervention of a person, please send those to
pilot-unix-owner@lists.best.com.
_______________________________________________________________________________________________
Copyright &copy; 1997, James McDuffie
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
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[ FRONT PAGE ]
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_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
Stronghold
: Undocumented Fun
By James Shelburne, brammal@iamerica.net
_______________________________________________________________________________________________
Disclaimer: Secure Socket Layer technology is a pretty touchy
legal matter. There's lots of money riding on it for a relatively small
number of companies. Therefore keep in mind that what I say in this article
may not be correct. If you plan to use Stronghold/Netscape (or any other SSL
server/client pair) for inter-office communication get legal advice, or make
sure you know what you're doing.
Also I won't go into some of the knowledge that I think you already
have, like the basics of public key cryptography or the fact that SSl URLs
are https:// instead of http://.
If you've looked for affordable ways to incorporate Secure Socket technology
into your intranet you've probably run into Stronghold. Although Stronghold
runs on platforms other than Linux it's a great, low resource intensive way,
to use a spare Linux box for providing encrypted/authenticated document
transfers over the Internet. This is perfect if you need to
&quotnetwork&quot; separate offices over the Internet without worrying about
prying eyes looking in on your document transfers.
The main problem you face when trying to use Stronghold for inter-office
communication is the lack of good documentation. Stronghold is mainly
intended for companies who want to receive credit card orders on-line. As
such, the installation scripts and documentation don't go into much detail
about setting up Certificate Authorities (more on this later) and the
features that allow you to not only have server authentication, but also
client authentication as well. To clarify things a bit I'll give you a short
"tutorial" on Secure Socket features. Since Netscape is the only
browser that currently has a decent Secure Socket Layer (or SSL from here on
out) implementation, I'll use that.
_______________________________________________________________________________________________
Netscape Security
Start up Netscape (3.0) and select Options -> Security
Preferences. Click on the tab that says Site Certificates. This
dialog box contains information about what Certificate Authorities your
browser currently recognizes and what level of trust you have assigned to
each. To illustrate this, select United States Postal Service CA and
click the button that says "Edit Certificate..."
Now you should see another dialog box pop up which contains various
information on that particular certificate. Notice the two fields:
"This certificate belongs to:" and "This certificate was
issued by:". In both cases it contains the same information. This means
that the certificate has been "self-signed" by the certificate
owner.
A little further down in the dialog box you'll see a pair of "radio
buttons" that allow you to either accept or deny connections from
secured Web sites that have been certified with this key. In other words, if
you allow connections from sites whose keys have been signed by the USPS
you're telling Netscape that you trust the USPS enough to certify
SSL-enabled Web servers and that no further proof of a server's identity is
needed. In reality, the USPS doesn't publicly certify keys (at least that I
know of), we're just using that as an example. The final check-box tells
Netscape to warn you before a secure connection is established to a Web
server that has been certified by this key. Click "Cancel" to exit
this dialog box.
If you connect to a site that has not been certified by one of the CAs
listed, all is not lost; you can still accept the individual site's key as
an individual "Site Certificate."We won't worry about this method
too much, but if you want to see which, if any, site certificates are
installed in Netscape then select Site Certificates from the drop-down
list above the "Site Certificate" list box. Note that, for some
reason, Certificate Authority certificates are considered
"Site Certificates."
What you've looked at here is enough for basic electronic commerce. In other
words, if you want to send sensitive information to a Web site, all you
really need to know is that the site is who it claims to be. The Certificate
Authorities listed provide this level of security. If you want to
use your Web server to distribute sensitive information to select
individuals, Server Authentication doesn't do you much good. Client
Authentication gives you the ability to authenticate the clients who connect
to your SSL Web server.
_______________________________________________________________________________________________
Client Authentication
Client Authentication of one of the neatest features of Netscape. In the
previous screen, select the tab that says Personal Certificates. If
you installed any Client Certificates (doubtful) they'll be here. If a
server requests Client Authentication, Netscape can perform one of three
actions:
1. Automatically decide which Client Certificate to send the server.
2. Let the user decide which Client Certificate to send to the server.
3. Send a particular Client Certificate to the server.
You can tell which action you want Netscape to perform by selecting the
appropriate option from the drop-down list in the "Personal
Certificates" dialog box.
Client certificates can be purchased from
various Certificate Authorities. This can get to be expensive if you want to
certify multiple client browsers, not to mention a hassle. Luckily
Stronghold comes with the basic tools that will allow you to create your own
small-time certificate authority that you can use to certify clients who
connect to your server and even other servers on your intranet.
_______________________________________________________________________________________________
A look at the files
There are lots of relevant files that Stronghold works with. I'll list the
main, non-HTTP-specific ones. I'll also assume you have installed the
program in the default directory (preferred).
/usr/local/ssl/private/YOUR-SERVER.key This is your server's
*private* key and should not be world-accessible at all. The way Stronghold
installed the directory "private" is chmod 700 root.
/usr/local/ssl/certs/YOUR-SERVER.cert This is where your servers
*public* key is located. This should be world-readable, and in fact your
server won't work in secure mode if it is not.
/usr/local/ssl/CA/rootcerts.pem This file contains the public keys
from the various CAs who issue Client Certificates. When your server wants
to check that a Client Certificate is actually issued by a valid CA it looks
in this file. This can be changed, but more on that later.
/usr/local/ssl/CA/cacert.pem When you start your own CA this file
will contain your public key. Note: This is not your server's public key.
/usr/local/ssl/CA/private/cakey.pem The private key for your CA
is stored here. As with all private keys, only root (or whatever username
you administer your CA under) should be able to see or change it.
/usr/local/ssl/CA/ssleay.conf AND /usr/local/ssl/lib/ssleay.conf For
one reason or another, Stronghold has two separate configuration files.
There is only a slight difference between them and Stronghold seems to want
to use them both so I'll describe the files as if they were one and point out
the differences as we come to them.
_______________________________________________________________________________________________
The ssleay.conf file
ssleay.conf is the main configuration file for Stronghold's key processing
tools. It's relatively complex but fairly well commented out so I won't go
into the whole thing, just a general overview and extra explanation where I
think it's necessary.
The thing that makes this configuration file different from what we've come
to expect from Linux (and UN*X in general) is the way it's subdivided. If
you've done much MS Windows programming you'll notice that it is divided
into key=value pairs and most sections also have an
"application name," for instance:
[ policy_match ]
countryName = match
stateOrProvinceName = match
organizationName = match
organizationalUnitName = optional
commonName = supplied
emailAddress = optional
In this section policy_match is the "application name" and
the rest are standard key=value pairs. Here the whole section can be
referenced by the label "policy_match"
_______________________________________________________________________________________________
Selected fields (from ssleay.conf):
default_crl_days: This "CRL" stumped me for a while. Apparently
it has to do with Certificate Revocation Lists, a feature that is not really
implemented in the SSleay toolkit (the package that was used to give
Stronghold it's SSL capabilities). Actually that's not completely true, the
CRL capability is there but CRL handling utilities aren't.
policy: The "policy" field lets you select which
policy you want to sign keys under. You probably won't need to mess with
this since, in most cases, you will check and sign keys by hand. If you want
to use a specific policy (check the Stronghold docs, what there is of them
;) ) change this field to "policy_match" and edit the policy_match
section below to reflect your chosen policy. The two possible values:
policy_match and policy_anything are
"application names" of the sections of the configuration file that
define who you will and will not sign keys for, or your "policy."
distinguished_name: There is only one difference between the two
different configuration files that Stronghold's key management tools use,
and this is it. This key=value pair will point to one of two
different "application names": req_distinguished_name or
makeca_distinguished_name. The only time it will point to
makeca_distinguished_name is when you are creating your own Certificate
Authority, the rest of the time it will point to
req_distinguished_name.
[makeca_distinguished_name]: This and the next entry are not
key=value pairs, but rather "application names" that define
particular groups of information.
The makeca_distinguished_name section of the file is only really referenced
when you first create your CA. Also you do
not need all of the fields that are included under this heading. For
instance, when I made my CA key pair I removed both
"organizationalUnitName" and "commonName." Because we
aren't dealing with slick commercial software, it may object if you start
altering this configuration file heavily.
[req_distinguished_name]: This section of the config file is where information on
machines to certify is kept. When you create a key-pair/signing request for
your SSl server with genkey, default information is looked up here.
Feel free to change some of the fields if you don't want this much info in
your keyfile. Beware, some commercial key signers (i.e. RSA or whoever) may
object to altered request formats. As before, your CA may choke if it gets a
request that has been highly altered. One field to especial watch out for is
"commonName," this is where Netscape looks to see if a web server
is using an appropriate keyfile for it's domain name. For example, if Netscape
tries to make a secure connection to www.insecure.org and the keyfile that
the server sends says it belongs to www.secure.org, you'll get a little
dialog box warning you about a possible security problem. If no
"commonName" is supplied, Netscape fails to connect and gives an
error-message.
_______________________________________________________________________________________________
The programs
genkey:Genkey is the program that is used to generate an initial
key-pair for your secure server and send out a signing request certificate
to your chosen CA. Before you run genkey make sure and create backup of both
your private and public keys for your Web server. After you make backups,
delete the original keys as genkey won't operate if it finds that a key-pair
already exists. Run the program like this:
genkey YOUR_SERVER_NAME
This will create a key-pair for your server and send out a Certificate
Signing Request (or CSR). Since we are going to create our own CA and sign
the key for the Web server with that, make sure that the CSR is sent to your
own e-mail address and not Verisign. Now you have generated an initial
key-pair and CSR. Get the CSR from your e-mail and save it for later.
Also note that the defaults for genkey are had from the
req_distinguished_name section of /usr/local/ssl/lib/ssleay.conf, if
there are fields you don't want included in your keyfile remove them from
this section.
makeca: Makeca is the program that is used to actually create your
Certificate Authority. This program gets it's default information from the
file /usr/local/ssl/CA/ssleay.conf in the makeca_distinguished_name
section (assuming you have installed everything in the default locations).
Makeca is executed without any arguments and is actually pretty intuitive.
As before, if there are entries that you don't want in your CA's keyfile
just remove their entries from the makeca_distinguished_name section
of the relevant configuration file.
ca: Ca is the actual program that you will use to perform
Certificate Authority functions. This includes signing other Web server keys
and Netscape's client keys. Assuming that you have been following along up
till now I'll assume that you have already used genkey to create a
key for your Web server and that you have mailed the CSR to yourself. To
sign your Web server's CSR save it as /tmp/csr and type the following:
ca -config /usr/local/ssl/lib/ssleay.conf -in /tmp/csr
ca will check the indicated configuration file to see what, if any, policy
has been defined for signing keys and ask you for your CA password. After
the key is signed it is stored in /usr/local/ssl/CA/new_cert/. New
certificates are not stored by name but by serial number, with the newest
cert having the highest number.
The cert is stored in PEM (Privacy Enhanced Mail) format and as such, can be
included in e-mail as is.
getca: Once you have a signed certificate for your Web server you
are ready to install it. Getca is the program for this and is called with:
getca YOUR_SERVER_NAME < /tmp/cert
We are assuming that /tmp/cert is your signed keyfile in PEM format.
One of the odd things about getca is that the input file must be
"piped" into the program.
If this went correctly your Web server should now have a public key signed
by your CA. Now for the tricky part...
_______________________________________________________________________________________________
Making Everything Work
Even though you now have a signed key certificate for your Web server you
still can't use it. This is because Netscape isn't aware of your CA, this is
to say that your CA isn't in the list of Site Certificates that we
looked at earlier. To add your CA to that list follow these steps:
1. Since the only (easy) way to install a key certificate in Netscape is through a Web
server you'll have to add a new MIME type. I added mine to the mime.types file by
adding a line like this:
application/x-x509-ca-cacert cacert
There are other ways to add MIME types that don't involve messing with config files but I
like the direct approach. Adding this MIME type tells Stronghold that every file that
ends with a .cacert extension should be sent as a Certificate Authority's public key.
2. The public key for your Certificate Authority is located in
/usr/local/ssl/CA/cacert.pem. The only problem here is that it in in PEM format and
Netscape expects CA keys to be in DER format. Luckily changing the format is pretty
painless, simply move into the same directory as cacert.pem and type the following:
x509 -outform DER cert.cacert
Like getca, x509 requires input and output to be "piped." In any event your key is now in
proper format and can be moved into one of your Web server's document directories.
3. Now point Netscape at your freshly converted CA certificate (cert.cacert). Since you've
added the appropriate MIME type Netscape will know that it is accepting a CA
certificate and will lead you though the process of installing it.
With that out of the way you should now see your CA's key when you look in
Netscape's
Site Certificates dialog box. Now, when you connect with
your Web server, Netscape will find the CA who signed the server's key and
try to locate it in it's database of CA certificates. Since we've just
installed your CA's certificate, Netscape should accept encrypted connections
from any site that has been signed by your CA.
_______________________________________________________________________________________________
Client Certificates
Creating Client Certificates for Netscape is a pretty complex task, and one
of the least documented features of SSL. All of Netscape's Client
Certificate functions work through a WWW interface, and as such you'll need
two special files: a HTML and a CGI, here are both:
key_req.cgi---------------------------------------------------------
#!/usr/bin/perl
read(STDIN,$input,$ENV{'CONTENT_LENGTH'});
open(TEST, ">/tmp/client_csr");
$input =~ s/\+/ /g;
$input =~ s/&/\n/g;
$input =~ s/%2B/\+/g;
$input =~ s/%2F/\//g;
$input =~ s/%3D/=/g;
$input =~ s/%0A//g;
print TEST ("$input");
print("Content-type: text/html\n\n$input\n");
--------------------------------------------------------------------
keygen.html---------------------------------------------------------
<HTML><HEAD>
<TITLE>Make akey</TITLE></HEAD><BODY>
<FORM ACTION="/cgi-bin/key_req.cgi" METHOD=POST>
E-mail: <br>
<INPUT TYPE="TEXT" NAME="Email" MAXLENGTH=40SIZE=40><br>
Common Name: <br>
<INPUT TYPE="TEXT" NAME="CN" MAXLENGTH=64 SIZE=64><br>
Organization Name: <br>&ltINPUT TYPE="TEXT" NAME="O"><br>
Organization Unit: <br><INPUT TYPE="TEXT" NAME="OU"><br>
Locality: <br><INPUT TYPE="TEXT" NAME="L"><br>
State or Province: <br><INPUT TYPE="TEXT" NAME="SP"><br>
Country (2 letter): <br>
<INPUT TYPE="TEXT" NAME="C" MAXLENGTH="2" SIZE="2"><br>
<KEYGEN NAME="SPKAC" CHALLENGE="testkeygen"><br>
<INPUT TYPE="submit" VALUE="Generate Key"></FORM>
</BODY></HTML>
--------------------------------------------------------------------
These files may need a little modification to work on your system, but they
should work like this:
keygen.html This is the actual HTML that Netscape needs to process a
key request. Like many things in Stronghold's SSL key management utilities,
you can omit just about whatever fields you want. For instance you might
want to only create keys that have an e-mail address and a name, for this
you would just remove everything except those two fields. This HTML was
snagged from the SSL user mailing list archive at
http://remus.prakinf.tu-ilmenau.de/ssl-users/
key_req.cgi This is the CGI program that will take Netscape's key
request and format it into something that your CA can understand and sign.
The script outputs two copies of the key request, the first goes to
/tmp/client_csr and the second is echoed back to Netscape as text.
_______________________________________________________________________________________________
Making A Signed Client Certificate
To create a Client Certificate signed by your CA follow these steps:
1. Assuming you have correctly installed both the CGI and HTML, load the HTML form into
Netscape. From the drop-down list select the key-size that you want. If you are using
the export version of Netscape you won't be able to choose a key size any larger than
512 bits. Fill in the fields with the desired information and select Generate Key.
Netscape will lead you through the steps of creating your key. When you see the text of
the client_csr echoed to the screen, you'll know that the script has been completed.
2. Go into your CA directory and type:
ca -spkac /tmp/client_csr -out /tmp/clientcert.der
You'll be asked for your CA password and, if all goes well, a signed Client Cert will be
output into /tmp/clientcert.der.
3. As with installing CA certificates Netscape needs a special MIME type telling it that a
particular file is a Client Certificate. Install this MIME type just like you installed
the previous one:
application/x-x509-user-cert der
This will tell Stronghold to use this MIME type for every file that ends in the .der
extension.
Whenever you change the configuration files you will have to restart the server so that
the changes will take effect. Stronghold comes with a script called reload that does
this for you.
4. Move clientcert.der into a directory of your Web server and point your copy of Netscape
at it. Netscape will then guide you through installing your new Client Certificate.
As you do this keep in mind that you won't be able to make a key with one copy of
Netscape and install the signed certificate in another. This is because every time
Netscape makes a key it keeps various information in a database file. Because it is in
a file you don't have to worry about creating the key and installing it in one session.
You can even shut down Netscape and install the key the next day without running into
any problems.
After the certificate is installed select Options -> Security
Preferences and click the Personal Certificates tab. Your new
Client Certificate should appear in the listbox.
If you're not the only person who has access to your machine, or even if you
*think* that you are. It's a good idea to password protect your Client
Certificate, this way someone won't be able to masquerade as you by simply
having access to your computer. In Options -> Security
Preferences, selecting the Passwords tab will bring up a dialog
box that will allow you to password protect your copy of Netscape. If you
set a password here it will will be used to actually encrypt your Client
Certificate(s). Loose this password and you're out of luck.
_______________________________________________________________________________________________
Client Authentication
Unfortunately client authentication isn't very advanced with any SSL Web
server package as of yet. In the future this will change so we might as well
get comfortable with SSL technology now, even though parts can get pretty
bumpy.
First we'll go through the steps to enable reliable Client Authentication
with Stronghold:
1. Open Stronghold's SSL configuration file in a text editor (httpsd.conf).
2. Enable SSLFakeBasicAuth. This will allow Stronghold to make limited decisions about who
should be allowed access to the server from the information it gets from Client
Certificates.
3. Set SSLVerifyClient to 2. This tells Stronghold that it must always verify clients who
want to connect to the server. If this isn't set then SSLFakeBasicAuth is pretty much
useless.
4. The SSLCACertificateFile directive tells Stronghold where to look for valid CA
certificates for checking signed client keys. Normally this points to the file
rootcerts.pem which contains public keys for a number of CAs that sign Client
Certificates. It's very important to point this to your own CA's public key file, in
this case cacert.pem. Doing this will only allow SSL connections from clients who have
had their keys signed by your CA, if you are using this for inter-office work, you will
want to do it this way.
Stronghold handles users in a different and more limited way than what most
webmasters are used to. For instance, in my Client Certificate I've only
included my Name and e-mail address. This way, Stronghold identifies me with
a string like this:
/CN=James Shelburne/Email=brammal@iamerica.net
If you will look at the source for the HTML form above you'll notice that
the "keys" are the same (i.e. CN for CommonName, Email for e-mail
address etc.). If I had included other fields in my certificate,
Stronghold would identify me by a larger list of "keys and
values."
_______________________________________________________________________________________________
Using SSLFakeBasicAuth
To test out SSLFakeBasicAuth insert a line like this in Stronghold's SSL
configuration file (Note: this only works in the SSL config file.
SSLFakeBasicAuth doesn't work with unencrypted HTTP transfers)
<Location /TEST_DIR>
AuthType Basic
AuthName Secret_Stuff
AuthUserFile /usr/local/apache/conf/ssl_user_file
<Limit GET POST>
require valid-user
</Limit>
</Location>
The file /usr/local/apache/conf/ssl_user_file (or whatever file you
choose to use) should contain the SSL identifier strings for each person
that you want to be able to access your SSL server. If I wanted to set up my
server so that I was the only one who would be able to access it, then the
only line in my ssl_user_file would be:
/CN=James Shelburne/Email=brammal@iamerica.net
When I try to make a secure connection to the server, Netscape will send the
Client Certificate made earlier. Stronghold will see that
SSLFakeBasicAuth is enabled and if I try and access /TEST_DIR, it will check
the users in the AuthUserFile to see if I'm there. If I'm in the file I'll
be granted access, if not, then access will be refused.
If you want to control access for a number of different user groups, feel free
to have multiple ssl_user_files each containing the identifying strings for the
people in that group. You might have ssl_accounting, ssl_sales and etc.
How do you find the strings that each user is identified by? When
SSLVerifyClient is set to 2 and a person tries to access a directory on the
server that is protected by SSLFakeBasicAuth the
user string comes up in the file /usr/local/apache/logs/ssl/access_log.
However, a better way to get the same information is
through the use of CGI environment variables, in particular
SSL_CLIENT_DN. Here's a short CGI script that when accessed through
SSL will display the user's identifying string:
CLIENT_DN displayer--------------------------------------------------
#!/usr/bin/perl
print <ltEOF
Content-type: text/html
&lthtml&gt<head>
<title>Your SSL_CLIENT_DN string</title></head><h3>Your SSL_CLIENT_DN string is:<br></h3>
&lth4&gt;$ENV{'SSL_CLIENT_DN'}</h4>
<html>
EOF
---------------------------------------------------------------------
There are other CGI environment variables but SSL_CLEINT_DN is the most
useful. If you know your way around CGI programming you can automate your
site on the basis of the SSL_CLIENT_DN variable.
_______________________________________________________________________________________________
Copyright &copy; 1997, James Shelburne
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
[ TABLE OF CONTENTS ]
[ FRONT PAGE ]
Back
Next
_______________________________________________________________________________________________
[IMAGE]
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
Usenix/Uselinux in Anaheim
By Phil Hughes, phil@ssc.com
_______________________________________________________________________________________________
Usenix/Uselinux Photo Album
_______________________________________________________________________________________________
Here I am at Usenix at the Mariott Hotel in Anaheim. Actually,
it is pleasant to be in nice weather after almost drowning in
Seattle. It had rained here the day before so the air
was actually clean. But, let me talk about the show instead of the weather.
Usenix is a five-day show that, this year, has a heavy Linux
presence. For those not familiar with Usenix, it has been the "wear a tie
and get laughed at" Unix show for years. It is technical
and tends to draw a very seriously technical crowd.
It is broken up into tutorials, a trade show and a technical
conference. Well, plus the informal beer drinking sessions and such.
_______________________________________________________________________________________________
Tutorial Days
The first two days are tutorials and I elected to attend an all-day
tutorial on the Linux 2.0 kernel presented by Stephen Tweedie. I found
it to be excellent and that seemed to be the general opinion of the
approximately 125 people who attended.
In eight hours and 170 overheads, Stephen addressed four specific
areas of the kernel: memory management, the scheduler, filesystems and
I/O and networking. I feel the goal of the talk, "to be with
the design and algorithms behind the Linux kernel and to be able
to read the Linux source code with some understanding"
was met. While Stephen did not necessarily expect attendees
to be familiar with Unix systems programming, the more you
knew about Unix the easier it was to understand the
presentation. After all, learning all about a new operating
system in eight hours is quite a challenge.
On Tuesday, Ted T'so taught a tutorial on writing device drivers under
Linux. This talk was attended by about 60 students. I elected to
take Tuesday as a day to catch up on LJ work and make a run to
Fry's Electronics to see if they carry Linux Journal. They
don't--which makes no sense as Fry's is exactly the
kind of place a Linux geek would want to go.
Tuesday evening started with free food and drink. This is one of
the best ways to get geeks talking. The Marriott did a great job
with an array of food carts with various choices including fruit,
veggies, potato patties, nachos, hamburgers and hot dogs. There
were also drink and dessert carts. They even had my drug of
choice, Dr. Pepper.
There were Birds-of-a-Feather sessions scheduled from 6PM
to 10PM. The two Linux ones were scheduled at the same time,
both at 7PM. As I already know a lot about Caldera Linux I
elected to go to the talk on Electronic Design Automation
(EDA). Peter Collins, manager of software services for
Exemplar Logic, headed the BoF and talked about how his
company had done an NT port but now had a Linux port. He
pointed out that EDA grew up on Unix-based systems like Suns and
the capabilities of Linux were a better fit for current EDA users.
_______________________________________________________________________________________________
The Trade Show
The trade show started on Wednesday. While this was not a Linux-specific
trade show, Linux had a large presence. Linux vendors included
Caldera, EST (makers of the bru backup utility), InfoMagic, Linux
International, Red Hat, Walnut Creek CDROM, Workgroup Solutions and
Yggdrasil. Plus, of course, our booth where we were giving away
sample copies of Linux Journal. Lots of other
vendors came by to talk about Linux and the Linux products they sell.
Linux interest was very high. While Usenix is a geek conference,
these are mostly professional geeks who are making serious technical
decisions for real companies. I answered many "It seems
like Linux could do this" inquiries.
Within the trade show I think SSC offered the biggest hit. We just
finished our new "fences" t-shirt. We sold out of the
shirts in about four hours on the first day. This gave me the
feeling that I was at the right show--not one where Microsoft
was being honored.
_______________________________________________________________________________________________
Linus Talks and Linux Talks
On Wednesday afternoon we proved how significant the Linux
interest/presence was. Linus was scheduled to talk on the future of
Linux in a fairly large room, which soon filled up, with standees
everywhere--including the hall outside. Usenix quickly offered
to move the crowd into a much larger hall.
The talk went well as Linus explained new features and new
ideas. I won't bore you with details. The important thing is that
the goal is world domination. To some this sounded like humor. Maybe
it was. Only time will tell. In the mean time, building a superior
product can't hurt.
Wednesday evening was a time for more Linux sessions. I attended
one called The Classroom of the Future that showed how an
experimental program brought the Internet to K-12 schools in
Ireland. I also attended another called The Future of the
Linux Desktop, missing Greg Wettstein's talk on perceptions. [see
Greg's article "Linux in the Trenches" in LJ #5,
September 1994--Ed.]
Thursday was another day of talks and trade show. Peter Struijk,
SSC's "head nerd" managed to make it to
Victor Yodaiken' presentation on real-time Linux [see
LJ #34, February 1997] and a talk on the /proc file system
by Stephen Tweedie. In the evening,
I hosted a session on embedded, turnkey and real-time systems and
intended to make it to Developing Linux-based electronic markets
for Internet Trading Experiments but ended up talking with
some of the attendees of my session instead.
The evening ended with a short talk about Linux and reality with
Stephen Tweedie and then a trip back to the hotel room to finish up
this column. Then, if I run out of things to do I may actually
get some sleep.
Friday offers a day of Uselinux business talks. However, the
combination of editorial deadlines and exhaustion mean that
you won't get to read about it here.
_______________________________________________________________________________________________
What Next?
It was a great show. Usenix has always been a great show offering
high-quality sessions and a really nice mix of
"non-suites". Having Usenix/Uselinux made it all the
better. I am sure there will be serious cooperation between Usenix and Linux
International to continue to make Linux a big part of Usenix.
If I have one complaint it was that there was too much to do. Add
a Linux International board meeting to a schedule that included
sessions, talks and BoFs from 9AM to 11PM with parallel Linux tracks
plus the normal Usenix tracks and there just wasn't time to breathe
or, more importantly, sit down to a beer and talk to fellow kernel
hackers, systems administrators or vendors.
Anyone who wants to get copies of the Proceedings of this
conference or find out what the future holds with regard to Usenix,
should contact USENIX Association at
office@usenix.org or check out their web site at
http://www.usenix.org/ or, if all else fails, call
510-528-8649. Oh, and if you don't know what 8649 spells you
must be new to the Unix community.
_______________________________________________________________________________________________
Copyright &copy; 1997, Phil Hughes
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
[ TABLE OF CONTENTS ]
[ FRONT PAGE ]
Back
Next
_______________________________________________________________________________________________
"Linux Gazette...making Linux just a little more lovable!" [IMAGE]
_______________________________________________________________________________________________
[IMAGE]
WELCOME TO THE LINUX WEEKEND MECHANIC!
Published in the February 1997 Edition of the Linux Gazette
Copyright (c) 1997 John M. Fisk <fiskjm@ctrvax.vanderbilt.edu>
The Linux Gazette is Copyright(c) 1997
Specialized Systems Consultants Inc.
_______________________________________________________________________________________________
Time To Become... The Linux Weekend Mechanic!
[IMAGE]
You've made it to the weekend and things have finally slowed down. You
crawl outa bed, bag the shave 'n shower 'cause it's Saturday, grab that
much needed cup of caffeine (your favorite alkaloid), and shuffle down
the hall to the den. It's time to fire up the Linux box, break out the
trusty 'ol Snap-On's, pop the hood, jack 'er up, and do a bit of
overhauling!
_______________________________________________________________________________________________
Table of Contents
* Welcome To the Weekend Mechanic!
* Supermount for 2.x Kernels!
* DOSEMU and WP 6.1 for DOS...
* X Window Wallpapering...!
* Closing up Shop...
_______________________________________________________________________________________________
[IMAGE] Howdy! Welcome to the Weekend Mechanic
Phew! It's good to be back!
So how's everyone doing? How are things going? I had a great semester
this past Fall -- got my 4.0 and everything :-) Still, things got rather
hectic toward the end of classes and I'm still trying to get myself
shoveled out from beneath a pile of backlogged email. I managed to survive
six finals, the usual glut of "end-of-the-semester projects",
a flight to Washington D.C. and a drive from there to N.Y. with my brother,
his wife, and three small boys to visit our parents for Christmas, a new HD
installation and complete system re-installation (the story of my life...),
AND I actually managed to show my face at work once or twice before classes
started again. If you're wondering why you haven't heard back from me,
hang in there, I'm coming... :-)
And is it only me, or does it seem that the 'ol Linux Gazette has really
taken on quite a nice face lift since Marjorie Richardson took the
helm...? I have to admit, the LG looks GREAT -- new graphics, better
organization, a search engine, and so forth. Having worked on the LG in
the past I know how much time and effort goes into each issue and I know
that Marjorie has worked hard on this. I know that a lot of folks have
taken the time to drop a note (the Mail section is as busy as it always
was... :-) but if you haven't, you really need to! Here, let me make it
easy for all of you with mail-capable browsers...
Dear Marjorie...
See! that wasn't so bad, and the reality of it is that demonstrated interest
and ongoing support are what keeps this 'ol ezine going in the first place!
Remember: "The masses may vote with their feet, but hackers
vote with both hands! (...unless you're able to type with your toes or are
gifted with a prehensile tail or something... :-)"
Anyway, drop Marjorie a note, she'll really appreciate it.
_______________________________________________________________________________________________
[IMAGE] Supermount for 2.x Kernels!
I don't know about you, but one of the things that I really missed
after doing the kernel 2.0 upgrade was being able to use supermount.
For those of you who are unfamiliar with it, supermount is a program
(in the form of a kernel patch) written by Stephen Tweedie that,
in effect, allows you to insert, take out, and re-insert removable media
such as floppies and CDs without going through all the rigmarole of using
mount and umount. For those of us who are converts from
the DOS era who are perpetually forgetting to umount a floppy before popping
it out of the drive, this comes as blessed succor.
And the good news is: IT'S BACK!
Actually, it probably wasn't gone all that long, truth be known. I've been
periodically checking in at the favorite sunsite.unc.edu mirror site
and peeking around the /pub/linux/kernel/patches/ subdir for a newer version
of supermount. No luck. Then recently, I saw a note posted by Stephen in
response to someone's query that the program was available for the 2.0
kernels. To break the suspense, here's the URL:
ftp://linux.dcs.ed.ac.uk/pub/linux/kernel/supermount/
There's a patch for kernel versions 2.0.0 and 2.0.23 and a README file that
outlines the fairly simple steps to applying the patch, recompiling the kernel
(and speaking of forgetting to do things, if you don't do a 'make zlilo' then
DON'T FORGET TO RERUN LILO if you install the new kernel), and setting up the
needed /etc/fstab entry to start using it. For those of you who've used
supermount in the past, you'll be pleased to know that the installation and
setup haven't changed since the kernel 1.2.13 version -- you should be able to
use your old /etc/fstab (if it's still lying around somewhere) and have things
come up working like they did in the Good Old Days!
Also, I wrote a short article on supermount several months ago for the LG and
mentioned that I'd had a lot of trouble getting it to work correctly with the
SoundBlaster 2X CD-ROM that I was using at the time. I was able to change CDs
but the directory listing simply wasn't being updated correctly. Well, after
the system upgrade this past Fall, I've switched to a Toshiba 8X CD and it
works fine with this. Which reminds me...
If you want to use supermount with a CD-ROM, at least with the ATAPI type drive
that I've got, then you'll likely want to make a small change to one of the
kernel files to allow the CD-ROM drive door to be opened when the drive has
been mounted. As most of you probably have noticed, once you mount the CD
drive, the door is locked -- you have to umount the drive in order to open it
and change CDs. Obviously, this doesn't work well if the point to using
supermount is NOT having to do this type of this. So, to disable door
locking, and PRESUMING YOU'RE USING AN ATAPI TYPE CD-ROM, then edit the file:
/usr/src/linux/drivers/block/ide-cd.c
Look for the following section which is near the beginning of the file:
/* Turning this on will disable the door-locking functionality.
This is apparently needed for supermount. */
#ifndef NO_DOOR_LOCKING
#define NO_DOOR_LOCKING 0
#endif
Change that '0' to a '1' after the NO_DOOR_LOCKING and you'll be all
set. This, as the quick-witted will have already surmised, does what it
implies: it disables door locking so you'll be able to change CDs. How
about that for easy, eh?
So, to summarize what you'll need to do, here's the brief rundown:
1. get your hands on the supermount patch (I'll help you with this one in a minute...)
2. apply the patch to the kernel:
$ cd /usr/src/linux
$ cp "path-to-patch"/supermount-0.4c-for-2.0.diff .
$ patch -s -p1
edit the /usr/src/linux/drivers/block/ide-cd.c file to disable door
locking
recompile your kernel AND RERUN LILO (ever get the idea that I've
forgotten to do this myself once or twice... :-)
edit your /etc/fstab to enable mounting of floppy or CD-ROM drives via
supermount
reboot the system to load the new kernel and enable supermount
Enjoy!!
Now, for the trusting (or merely lazy like myself... :-), here's a copy of the
patches and the README file:
supermount-0.4c-for-2.0.23.diff
supermount-0.4c-for-2.0.diff
supermount.README
If you're the suspicious or just plain cautious type then go ahead and get the
files from the URL above. Also, you might want to check there for updates or
newer releases.
One thing that I've not really tried yet is seeing what happens if the CD-ROM
drive is mounted via supermount and you attempt to play an audio CD. I've not
had the nerve to try this. In this case, it's probably safe to go ahead and
umount the drive, play the CD, and then mount the drive once again -- since
there's an entry for the CD-ROM drive in /etc/fstab, all you should have to do
is something like:
mount /cdrom
presuming that /cdrom is where you normally mount your CD.
The other thing that I've not tried is using supermount with BOTH ext2 and
MS-DOS type floppies. I suspect that it would cause a bit of trouble but,
again, I've not been daring (or foolish...?) enough to try this little
maneuver.
Anyway, I hope that give supermount a try! The README file is pretty helpful
in terms of answering basic setup and usage questions and he includes a copy
of his /etc/fstab file as an example. Hope you enjoy!
John
Nashville, TN
Mon Jan 20 10:26:51 CST 1997
_______________________________________________________________________________________________
[IMAGE] DOSEMU and WP 6.1 for DOS...
I hesitate to even bring this up... :-)
One of the more common USENET postings in almost any of the linux
groups these days is some newbee who innocently ventures a question such as
"Is there a word processor for Linux like Word for Windows...".
After the poor bloke gets flamed to a crisp with ardent admonitions to eschew
such lollipop-ware and use a real text-processing system such as
LaTeX or GROFF, there usually ensues a heated debate over the virtues of one's
favorite system for getting something into print...
I think I'd like to avoid such debate... :-)
I would, however, like to humbly offer one possible solution to the need for a
word processor under Linux -- especially if you're either unfamiliar with
LaTeX or find that it doesn't completely meet your text-processing needs. And
that is, using DOSEMU and one of the common word processors available
for DOS. Now, if you already have a system working for you then by all means
stick with it! However, if you still find yourself rebooting to DOS, OS/2, or
Windows to do a bit of word processing then this might be one possible
alternative.
But before I go on...
Let me quickly mention that I'm well aware that the usual business apps which
have long been available for the other OS's -- the word processors,
spreadsheets, desktop publishing packages, PIMs, and so forth -- are starting
to appear as Linux-native applications! This is great news and I
certainly welcome and support such efforts to bring these much-needed tools to
the the Linux OS! Thing is, what I've tried so far really hasn't been helpful
for me. To wit:
* LyX -- a VERY nice, near-WYSIWYG front-end to the LaTeX text processing system. I've
just now started to spend some time with this. One of the things that I've really liked
about this is that it uses a system that is native to Linux and UNIX -- LaTeX. It means
that the documents are portable and render in a reliable manner. For my own tastes, the
fonts sometimes appear a bit old, but that's strictly my own tastes. I think this holds
a lot of promise.
* StarOffice -- I think that this also holds a LOT of promise. It's currently freely
available as beta software and has a very modern installation routine and very handsome
UI (to my conceits). My own pet peeve about it is the frequency in which I get warnings
about the version expiring and the (admittedly minor) irritation of having to download
a whole new set of files and doing the installation all over again.
My other fairly minor complaint with it is the look of the output -- I've not been
terribly impressed with the set of default fonts that come with it. Again, this is
strictly a matter of taste, but the output hasn't been exactly what I'd hoped for..
* EZ -- The EZ word processor is part of the Andrew User Interface System (aka, AUIS) and
really is a fairly easy to use word processor. Overall, I've been pleased with its ease
of installation and use and the output is generally quite acceptable. The range of
fonts is a bit limited, but for short notes and memos it's quite useful. I've not spent
enough time with this to really ascertain the full extent of its customizations. I
suspect that it's capable of more than I'm currently doing if I only knew how...
* I've also played around some with a few of the other available word processors --
SciTeXt, Thot, and Papyrus. They all seem to be "works in progress" and show promise.
Still, I've not found that the output equals what I've been able to achieve using the
usual DOS, OS/2, Win, or Mac apps.
Sorry, call me a heretic... :-)
I really don't want to get mired down in a review of all the possible word
processor tools out there -- I mention these in order to say, "I've given
them a a try..." Two other applications that really deserve to be
mentioned include the Caldera's WordPerfect for Linux and the
Applixware Suite available through Red Hat Software. I've not had a
chance to try either of these out, although I've read a good deal of pro's and
con's about each of them in the linux USENET hierarchy. A buddy at school
just got a copy of the academic version of Applixware and I'm pretty
interested in seeing this in action. So far, he's been pretty pleased with
it, so I definitely need to stop by and give this a try!
Anyway, what I've found is working quite well for me is a combination of
DOSEMU and WordPerfect 6.1 for DOS. If you happen to have an old (or new)
copy of WP for DOS available to you, and you're willing to give DOSEMU a
whirl, let me urge you to give this a try.
At this point, I'm going to do something I swore to myself I'd never do -- I'm
going to weenie out on you a NOT go through the entire process of setting up
DOSEMU. The reason for this is that, although I've gotten it up and running
on my own box at home here, I really don't feel terribly comfortable with
being able to walk anyone else through the process. I ended up tinkering
around with it and, through an admittedly haphazard process of trial &
(mostly) error, got the thing to work. There are still several things about
it that I don't understand and so I won't inflict my ignorance upon you.
Still with me... :-)
Thing is, there's a very helpful little file that comes with DOSEMU called
"QuickStart" that goes through the setup process step-by-step. If a
Neanderthal like me can get this working, I'm confident that you can too!
What I would like to do is present a brief synopsis of my experiences with
this in the hopes that it might be helpful to someone trying the same things.
Again, let me emphasize that this represents strictly my own
experiences. As the old saying goes, "your mileage may vary..."
DOSEMU SETUP
After upgrading to kernel 2.0 I found it necessary to upgrade a number of
packages, including DOSEMU. At the time, I picked up the most recent version
which was dosemu-0.63.1.36. The configuration, compilation, and installation
were as simple as:
$ ./configure
$ make
$ make install
This defaulted to including DPMI support, requiring the emumodule and
syscallmgr modules to be loaded before being able to use DOSEMU. DPMI support
allows you to try your hand at booting up Windows under DOSEMU. Over the past
few months I've had mixed success at best in doing this. Also, since this is
not currently supported by the DOSEMU folks, you're completely on your own if
you want to venture into this! :-)
After compiling and installing the binaries, I used the QuickStart file as a
guide and created the needed /etc/dosemu.conf and /etc/dosemu.users files.
DOSEMU comes with a heavily commented configuration file -- dosemu.conf
-- that let's you customize in a rational manner. For the curious, here's my
current working version of dosemu.conf:
/etc/dosemu.conf example file
Let me make a couple comments about this before going on:
* I set rawkeyboard to on. This allows the full use of all the WP keystroke combinations.
I found that without this, some of the usual key combinations simply weren't working. I
was able to use the menus without any problem at all, but I still wanted to be able to
keep my hands on the keyboard.
Be aware that if you do this, there's a chance that if DOSEMU crashes it will not
correctly reset the keyboard and could potential require a cold boot (or a remote
'kbd_mode -a' to reset it). See the comments in the dosemu.conf file about this.
* I also wanted to get mouse support working. I found that the internal mouse driver that
comes with DOSEMU worked fine for most programs but didn't seem to work for WP. You'll
notice that I commented that section out and set up the Serial stuff so that I could
load my own mouse driver from DOS.
* Under the Video section, I found that I was able to get decent text-mode AND
graphics-mode support using the S3 chipset support. I've got a Diamond Stealth 64 Video
VRAM with 2MB of memory and this has worked great. There are a number of warnings in
this section of dosemu.conf and it would be advisable to read carefully through them.
* Finally, I really needed to have printer support if this was to be a viable solution at
all. I've been using the apsfilter program for some time now and really love this a
LOT. One of the printer modes that it sets up is 'raw' mode and I found that this was
the key to being able to print from DOS. Printer support uses lpr, and by using the
"-Praw" option I was able to get printing to work. I also set up raw access to the lpt1
port.
After doing all of this (in an incremental fashion) I found myself with a
working version of DOSEMU and a functional WP program!
I also decided to load the emumodule and syscallmgr modules at boot time so
that I could use DOSEMU more easily. To do so, you'll probably want to the
use 'insmod' program that gets compiled with the rest of the DOSEMU files.
The easy way to do this is to use the 'load_module.sh' script in the root DOSEMU
directory. I found that by editing the first couple lines of the script I was
able to call it from any directory: just add the correct path names at the
top:
#!/bin/bash
MODULESDIR=/usr/local/lib/dosemu-0.63.1.36/0.63.1.36/modules
BINDIR=/usr/local/lib/dosemu-0.63.1.36/bin
[...]
and then add a stanza to /etc/rc.d/rc.local such as:
if [ -x /usr/local/lib/dosemu-0.63.1.36/load_module.sh ]; then
echo "Loading DOSEMU 0.63 modules..."
. /usr/local/lib/dosemu-0.63.1.36/load_module.sh
fi
The modules use up very little memory and the convenience of not having to
remember to load them is probably worthwhile.
INSTALLING WORDPERFECT 6.1 FOR DOS
There really isn't an awful lot of startling news here -- if you're used to
installing DOS programs then this is pretty much a "no-brainer".
The one important point to make, however, has to do with video driver
installation. I discovered something quite valuable recently when I
re-installed my system over Christmas Break.
The first time I set up WP 6.1 I installed only the S3 drivers (since
I'm using an S3-based Diamond card). I found that doing so provided
graphics mode support under DOS in resolutions up to 1280x1024. However,
I was keenly disappointed to find that the best graphics-mode resolution
I could get under DOSEMU was an abysmal 320x200. No matter how I poked,
prodded, wheedled, cajoled, threatened, and messed with it, that's all I got.
Serious Bummer... :-(
Over Christmas, when I reinstalled the system, I noticed that one of the video
drivers was labeled simply "VESA" and so, on a whim, installed that
as well as the S3 drivers. This turned out to be quite fortuitous as although
the S3 drivers still did not give better than 320x200 resolution, the VESA
driver actually allowed me to get 1024x768 in 8-bit color. On a 17" monitor,
this is a very comfortable resolution and provides pretty good WYSIWYG
previewing.
So, the moral of the story is -- if you're in doubt, give the VESA video
drivers a whirl.
RUNNING WORDPERFECT 6.1 UNDER DOSEMU
Once I got DOSEMU installed and properly configured (BTW, I also created the
/etc/dosemu.users file that simply has the word "all" as the sole
word on the first line -- this let's anyone (i.e., me) to execute the
program) and WP 6.1 installed, I was quite pleased to discover that nearly all
the features available from running it under DOS were also available under
DOSEMU:
* full mouse support
* full text mode support
* graphics mode for WYSIWYG editing and print preview to 1024x768 in 256 colors
* support for all keystroke combinations
The one feature that I haven't yet tried is fax support, although ostensibly
it should work.
A feature of WP that is completely UNAVAILABLE under DOS is that I can be
editing a file in WP under DOSEMU and, using Ctrl-Alt-Fn, switch to another
virtual terminal and continue to work under Linux. Running X Window
concurrently also has shown no signs of causing problems.
Let me say this again since I get a chill just thinking about it...
I can run DOSEMU + WP 6.1 in a virtual terminal and have full editing and
printing capabilities while at the same time freely switch to another VT or
even to X Window and have all these processes running concurrently!!
This is what makes Linux such a seriously cool OS!!
This is way too cool... ;-)
The one caveat I'd mention is that of using WP in graphics mode. I don't know
about WP 5.1, but version 6.1 supports a fairly respectable graphics-mode that
provides WYSIWYG editing and print preview. On my system, the performance is
quite acceptable, although not quite as responsive as under DOS (but then
who'd want to run anything under DOS if they didn't really need to... :-)
However, switching to a VT or to an X Window session while in graphics mode
renders the system completely unusable -- the keyboard AND the console both
go into impenetrable lockup which only a cold boot fixes. This has, at least,
been my experience. However, I found that if I simply exited back to text
mode before switching to another VT then everything worked fine.
Finally, let me make one last comment about using WP under DOSEMU. One of my
ongoing complaints about many (though certainly not all) of the current
"word processors" available for Linux is the quality of the printed
output. The features that drew me to using WP were the familiarity with the
program and the quality of the final output. WP 6.1 supports, among other
things, TrueType fonts and having invested in a Corel Draw some time back (and
its 750+ TT fonts) I was pretty keen to being able to continue to use these.
I've been quite pleased that under Linux I can still do basic word processing
in a known environment with predictable output. That was the clincher for me.
Again, let me quickly add that this might not be at all what you want or you
might simply dislike the WP system itself. The thing about Linux is that it
give you a choice once again!
And, for the skeptics out there, those who said, "it can't be
done...", here's a screen shot of WP 6.1 running under X...
screen shot of WP 6.1 running under xdos
Give this a try! If you like it, keep it. If not, delete it and have
a look at something else. Also, if you're looking for something to run
under X then you might be well served to give either the Applixware suite
or the Linux WordPerfect port a try. DOSEMU will run under X (as xdos)
but WP loses some of its functionality -- mouse support and keystroke
support can be a bit flaky and graphics-mode support is completely lost.
So, if X is where you spend most of your time, you might consider investing
in or investigating one of the native X programs.
Most of all, though...
Have Fun & Happy Linux'ing!
John
Nashville, TN
Mon Jan 20 13:18:01 CST 1997
_______________________________________________________________________________________________
[IMAGE] X Window Wallpapering...!
Well, here's a little nothingburger that comes pretty close to being a bona
fide FAQ -- the question arises from time to time as to how to
(automatically) wallpaper one's X Window session after starting X. For the
impatient, the short answer is:
xv -quit -root image.gif
Presuming, of course, that the image that you wanted to use was in fact called
"image.gif" the above would use the ubiquitous xv program by
John Bradley to tile your root window with the specified window. The
"-quit" option causes xv to do its work and then quietly terminate.
If you're using one of the 1.x versions of FVWM then just add a stanza such as
the following:
Function "InitFunction"
Exec "I" exec /usr/X11/bin/xv -quit -root /usr/gx/image.gif &
[...]
EndFunction
That is, you simply add a stanza for xv to the "InitFunction" and
this is done automatically!
Since I've not upgraded to the newer FVWM 2.x version (nor FVWM-95, or any of
the other myriad new window managers) you're rather on your own with this one.
However, I suspect that a quick perusal of the manual page or the
configuration file should quickly point the way.
At the moment, I'm using olvwm 4 (with the 3.2 libraries) and added the
following to the /var/openwin/lib/Xinitrc file:
#!/bin/sh
# Xinitrc executed by openwin script to display startup logo
# and restore desktop setup (saved using owplaces)
# Hereby placed into public domain by Kenneth Osterberg 1993.
[...]
# Start programs
exec /usr/X11/bin/xv -quit -root /var/openwin/lib/marbleFlowers.gif &</b>
exec /usr/local/X11/bin/xcalendar -geometry 240x240+0+160 &
exec /usr/X11/bin/xclock -geometry 134x127+252+0 &
exec /usr/local/X11/bin/rxvt -ls -font 9x15 -geometry 80x32+500+195 &
exec /usr/local/X11/bin/rxvt -ls -font 9x15 -geometry 79x31+252+268 &
exec /home/fiskjm/bin/syslogtk -geometry +398+0 &
# Startup the OpenLook window manager
if [ ! -z "$WINDOWMANAGER" ]; then
exec $WINDOWMANAGER
else
exec $OPENWINHOME/bin/olwm
fi
This has the identical effect of tiling the root window before olvwm is
launched.
If you're interested in this, there are actually all sorts of nifty things
that you can play with along this line. Keep in mind that xv has a plethora
of options for setting the root window image interactively. To do so, simply
find an image that you'd like to play with, launch xv with the image filename
as the argument, and then select the "Root" button. I won't list
all the possible options -- try them out and amuse yourself!
Thing is, to really have a good time you need to have a few images to play
with and question is, where to get these little rascals...?
Well...
Here's a couple ideas to get you going:
* If you're running Windows, Win95, or OS/2 then you have to look no farther than your C:
drive! XV is more than capable of handling the *.BMP files from Windows and converting
them to .GIF or .JPG (or any of several other formats for that matter) files. I'll use
this as an example in a minute...
* For those of you wanting to get rid of the... er... Windows motif and if you're
connected to the INTERNET, then the world is your oyster, my friend!!
There are all KINDS of great images out there that you can play with. FWIW, the GIMP
home page has a fantastic marble tile image on its front page. It's wallpapering my
desktop at this moment.
You might also do a quick Yahoo, Alta Vista, or WebCrawler search for any of the
numerous Online Art Museums and Art Galleries. Or, for all you 60's Baby Boomers who
grew up watching the Apollo flights and dreamt of being an astronaut, check out NASA's
huge collection of space related images. If you're a Netscape user, simply click the
right mouse button over the image and save it to disk. Keep in mind that some images do
have copyright protection.
* For those do-it-yourself'ers out there with a bit of talent, you can easily play around
with programs such as xpaint and draw your own or modify an image to your likings.
One of the other fun programs to play with is xfractint which generates fractal images.
It will also SAVE those images in GIF format.
Anyway, you get the picture. If you have a scanner, then you're golden :-)
So let's do a quick walk through on this.
After I somewhat reluctantly installed Win95 this past Fall (I was taking a
Visual Programming class and you can guess as to which Visual language we had
to use...) I discovered a few new wallpaper images including one that I really
liked -- the Forest.bmp image. I happen to enjoy hiking around in the nearby
Great Smoky Mountains and grew up in the pine forests of upstate New York.
Anyway, I decided that I'd gotten a bit tired of the 'ol SteelBlue background
and was ready for a change. Here's what I did...
After mounting my Win95 partition and copying the c:\win95\Forest.bmp file to
my home directory I used xv to have a look at this rascal and convert it to a
GIF image. XV allows you to save an image as any number of different formats
and I chose GIF, Full Color. That done, I had a suspicion that this might be
a bit of a color resource hog -- a suspicion that was confirmed by another
handy little program, xli.
Xli is a graphics manipulation program that is easily found at any of the
sunsite mirrors in the
X11 directory under the graphics viewers subdirectory. One of its handy
features is the "identification" mode that it can run in. To get
information about an image (from the command line) simply type in:
xli -ident image.gif
and assuming that the image you were interested was, in fact, named
"image.gif" then it would print out a useful one-liner. Doing this
to the Forest.gif image that we just created using xv, we find:
$ xli -ident ~/Forest.gif
/home/fiskjm/Forest.gif is a 256x256 GIF87a image with 256 colors
Hmm... the size is OK, but with 256 colors this will definitely burn out my
color map quicker than you can say Netscape! Now, enter the next useful
program to our arsenal of image tools -- ImageMagick.
ImageMagick is one of those seriously cool, Must-Have programs if you're
playing around with images very often. I recently found the latest version
(nicely pre-compiled, thank you...) at the
GA Tech sunsite
mirror (ImageMagick-3.7.9-tgz) along with the needed libraries
(libIMPlugin-1.0-tgz). Installing the precompiled bin's was a no-brainer and
I was up and running in no time flat.
One of the programs that is included with ImageMagick (it's actually a suite
of programs) is convert. convert allows you to quickly and
easily convert images from one format to another and to optionally set its
various attributes. You need to have a look at the manual page (which is
included with the binaries) to really appreciate all the things this is
capable of doing. For what I was trying to do, all I needed was to set the
size of the color map to something a bit more sane.
Using the "-colors" option I was able to set the "preferred
number of colors" to something that was a bit more X friendly:
convert -colors 32 ~/Forest.gif ~/forest.gif
Doing this and running xli on it once again, we find that it has, in fact,
been stripped down to a more lean 32 colors:
xli -ident ~/forest.gif
~/forest.gif is a 256x256 interlaced GIF89a image with 32 colors
That's a bit better. Now I suppose that I could have used an even smaller
number but 32 colors gave an image that differed visually from the original
image very little.
Anyway, that was it! I now had a 256x256 image with 32 colors that no longer
threatened to burn out my entire color map! I added a stanza to the Xinitrc
file and voila!, instant wallpaper!
Keep in mind that this is hardly the only way to do this. There are
several other nifty programs out there that provide similar functionality.
Try scrounging around in the X11/graphics/ subdirectory of any of the sunsite
mirrors or at ftp.x.org in its contrib
subdirectory.
Another program that I'll mention before closing this up is the truly awesome
xearth program. If you're looking for a truly impressive, animated X
wallpaper program, look no further. This is one way too cool program! I
don't have a screen shot of it to show you but believe me, it's worth setting
it up and giving it a whirl! At the moment, you should be able to find it in
the
/X11/xapps/graphics/ subdirectory of any of the sunsite Linux mirrors.
The file to look for is xearth-1.0.tgz.
Anyway, hope this gets you going! I admit that it's been a bit of a
smorgasbord of suggestions, but you might be able to find something useful
here! :-)
As usual, hope you enjoy!
John
Nashville, TN
Mon Jan 20 21:08:25 CST 1997
_______________________________________________________________________________________________
[IMAGE] Closing Up Shop...
Well, as usual, things around here have been busier than I'd hoped and I just
don't have the time to do all of the writing that I'd like to. Also, I'm
trying to keep this page to a reasonable size :-) (those of you who've been
hanging around here for a while might remember those 160K+ size pages...).
So what has everyone been up to? Found any new toys... :-)
Over Christmas, I finally started working on something that I'd been
promising to do for ages: I've started to learn emacs! I have to say that
this has been a bit of a paradigm shift after having used VIM for such a long
time. However, I can see why the loyalties run so deep -- Emacs is a
seriously cool and indisputably powerful editor. Truth is, however, that I've
not taken the purist approach: I have to admit that I'm really using
XEmacs. I also got my hands on an xemacs-derivative called
infodock which is another way-too-cool and VERY powerful editor.
I'd hoped to write a bit on my initial experiences and impressions but I guess
that will have to wait for another month or so. Thing is, there are actually
quite a number of GREAT editors out there to mess around with. And the more
that I try out different ones (I've decided that I really am an "editor
junkie...") the more I'm convinced that the essence of the editor flame
wars that periodically erupt can be summed up in preference.
Not to throw a wet blanket on anyone's jihad, but...
Although feature sets, user interfaces, resource utilization, performance
issues, and so forth are very valid issues when discussing the various merits
and liabilities of one's favorite editor, the bottom line is: you probably
use it because you like it! I have to admit that after using VIM for the past
couple years, emacs is something of an acquired taste. However, if
you've been using emacs for a while, then vi looks a bit stark and your
fingers feel bewildered.
Anyway, there's no accounting for taste and no apologies for it either. The
great thing about Linux is that "it restores the choice once again!"
Try everything out, use what is useful, keep what you like. And FWIW, those
of you using a VI clone like myself might be interested in giving the latest
iteration of VIM a test drive. As of a little bit ago, VIM 4.5 source was in
the sunsite Incoming directory. It can now be compiled, using the Motif
widget set, to have both a console-based and an honest-to-goodness X-based
interface. The X version is called gvim (for "Graphical
VIM") and I'm using it right now. It has all of the usual keystrokes
(for all you ten-fingered typers...) but has nice mouse support for cursor
positioning and cut-and-paste operations. It also sports a handsome
scrollbar, handles multiple windows with aplomb, and even touts a rudimentary
but useful menu bar. It has a very extensive online help system that is
vaguely hypertext-like: you can navigate from one "node" to another
using a keystroke similar to that with tags: Ctrl-] selects a node and Ctrl-t
returns you to the original location.
With any luck, I'll have some time this next month and will try to put
something together -- mostly just chat, nothing terribly profound. I've got a
few screen dumps for the visually-oriented. Those of you who are considering
taking the leap and learning emacs might well be served to have a look at
this rascal. AND, keep in mind that it is NOT just an X Window app -- it'll
run in console mode just as easily as under X. Have a look at the XEmacs home
page for more info:
WWW.XEMACS.ORG
AND WHILE YOU'RE THERE, HAVE A PEEK AT THE
infodock stuff as well.
Finally, in this month's Linux Journal there's a very nice article by
an old LG regular: Larry Ayers, who has written a review comparing GNU
Emacs with XEmacs. For the curious, it's well worth having a look at what
Larry's impressions of the two were.
Well, I've got a bit of work to get one tonight and so I'll wrap this up for
the month. I'm still trying to get out from underneath a pile of
email. Hang in there... I'm coming!
Best Wishes and Happy Linux'ing!!
John M. Fisk
Nashville, TN
Monday, January 27, 1997
_______________________________________________________________________________________________
[IMAGE] If you'd like,
drop me a note at:
John M. Fisk <fiskjm@ctrvax.vanderbilt.edu>
Version Information:
$Id: issue14.txt,v 1.1.1.1 2002/08/14 22:26:57 dan Exp $
_______________________________________________________________________________________________
Copyright &copy; 1997, John M. Fisk
Published in Issue 14 of the Linux Gazette
_______________________________________________________________________________________________
[ TABLE OF CONTENTS ]
[ FRONT PAGE ]
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_______________________________________________________________________________________________
[IMAGE]
LINUX GAZETTE BACK PAGE
Copyright &copy; 1997 Specialized Systems Consultants, Inc.
For information regarding copying and distribution of this material see the Copying License.
_______________________________________________________________________________________________
CONTENTS:
* About This Month's Authors
* Not Linux
[IMAGE]
_______________________________________________________________________________________________
ABOUT THIS MONTH'S AUTHORS
_______________________________________________________________________________________________
Larry Ayers
Larry Ayers lives on a small farm
in northern Missouri, where he is currently engaged in building a
timber-frame house for his family. He operates a portable band-saw mill,
does general woodworking, plays the fiddle and searches for rare
prairie plants, as well as growing shiitake mushrooms. He is also
struggling with configuring a Usenet news server for his local ISP.
John M. Fisk
John Fisk is most noteworthy as the former editor of the
Linux Gazette.
After three years as a General Surgery resident and
Research Fellow at the Vanderbilt University Medical Center,
John decided to "hang up the stethoscope", and pursue a
career in Medical Information Management. He's currently a full
time student at the Middle Tennessee State University and hopes
to complete a graduate degree in Computer Science before
entering a Medical Informatics Fellowship. In his dwindling
free time he and his wife Faith enjoy hiking and camping in
Tennessee's beautiful Great Smoky Mountains. He has been an avid Linux fan,
since his first Slackware 2.0.0 installation a year and a half
ago.
Jim Dennis
Jim Dennis
is the proprietor of
Starshine Technical Services.
His professional experience includes work in the technical
support, quality assurance, and information services (MIS)
departments of software companies like
Quarterdeck,
Symantec/
Peter Norton Group, and
McAfee Associates -- as well as
positions (field service rep) with smaller VAR's.
He's been using Linux since version 0.99p10 and is an active
participant on an ever-changing list of mailing lists and
newsgroups. He's just started collaborating on the 2nd Edition
for a book on Unix systems administration.
Jim is an avid science fiction fan -- and recently got
married at the World Science Fiction Convention in Anaheim.
Grant B. Gustafson
Grant Gustafson is Professor of Mathematics, the
University of Utah, Salt Lake City. Besides
differential equations, he has an interest in
microcomputers (since 1978), compilers, programming
languages, system utilities and TeX typesetting.
Michael J. Hammel
Michael J. Hammel,
is a transient software engineer with a background in
everything from data communications to GUI development to Interactive Cable
systems--all based in Unix. His interests outside of computers
include 5K/10K races, skiing, Thai food and gardening. He suggests if you
have any serious interest in finding out more about him, you visit his home
pages at http://www.csn.net/~mjhammel. You'll find out more
there than you really wanted to know.
Phil Hughes
Phil Hughes is the publisher of
Linux Journal, and thereby Linux
Gazette. He dreams of permanently tele-commuting from his home on the
Pacific coast of the Olympic Peninsula. As an employer, he is "Vicious, Evil,
Mean, & Nasty, but kind of mellow" as a boss should be.
Mike List
Mike List is a father of four teenagers, musician, printer (not
laserjet), and recently reformed technophobe, who has been into computers
since April,1996, and Linux since July.
R. Frank Louden
Frank Louden has a degree in Computer Science from Purdue.
While working on his degree, he also worked in the Medical center first as a
Computer Clerk then as the Systems Manager.
He currently works as a Programmer, which "is all the fun and a lot
fewer headaches (read: It sounds like a hardware problem to me.)"
He first installed Linux last March, so he knows the challenge a convert
faces.
On the personal side, he lives in a small town in north central Indiana and
would love to organize a LUG but thinks it'd be difficult to find
any other Linux users out here in the boonies. He has two cats, Mac and
Catalina who he says "both know more about Linux than I do...but they never
reveal their secrets!"
James McDuffie
James McDuffie is a 17 year old high school student who is looking forward
to graduating. In college he plans to major in Computer Science
and minor in English. He would like to be a writer while still
working with computers. James wrote the article Connecting Computers via
PLIP which appeared in issue #6 of the Linux Gazette. He has been an avid
reader of the Linux Gazette ever since it was just starting out. And wishes
that it continues helping the Linux community for some time to come.
James Shelburne
James Shelburne currently lives in Waco, Texas where he spends most of
his free time working on various Linux networking projects. Some of his
interests include Perl + CGI, Russian, herbal medicine and the Ramones
(yes, you heard right, the Ramones). He is also a staunch Linux advocate
and tries to convert every MacOS/MS Windows/AMIGA user he comes into
contact with. Needless to say, only other Linux users can stand him.
Kelley Spoon
Kelley Spoon currently studies computer science at the University of Texas,
San Antonio. Some of his hobbies include trying to learn how to play the
guitar, playing Euchre, laughing at John C. Dvorak, converting pizza into
source code, terrorizing villages along the Mexican border, and frightening
small childern. He has been a Linux user since August 1995, and still
pronounces the name as "luh-eye-nucks".
Kelly has written another article for us about tcpd that will appear in
issue 15 of Linux Gazette.
Jens Wessling
Jens Wessling is a 26 year old Research Scientist working for the
Environmental Research Institute of Michigan. He has been
playing with Linux since Kernel 1.0.99. He is
married and has 2 cats. He is currently working on his
Masters Degree in Computer and Information Science
at the University of Michigan. Life frequently gets in his way.
Joel Wilf
Joel Wilf is a technical writer with a strong interest in
computers and multimedia. He is also a screenwriter, whose
credits include
Supercarrier and Outsiders. Writing a
script-formatting utility, under DOS, led him to the richer
programming and text-processing environment of Linux. Offline,
he enjoys reading and traveling. He lives in Encino,
California.
[IMAGE]
_______________________________________________________________________________________________
NOT LINUX
_______________________________________________________________________________________________
Thanks to all our authors, not just the ones above, but also those who wrote
giving us their tips and tricks and making suggestions. Thanks also to our
new mirror sites. We get new ones every month. I was very excited to have
both one in Russia and the new Italian translation site go up this month.
(See the Mirror Page.)
My two favorite holidays are Valentine's Day and Halloween. Not sure I want
to know what that little fact may have to say about my psyche. At any rate I hope
the animated heart wasn't too annoying. I thought it was quite cute. Thanks
to Michael, our web guy, for finding it and the roses to present to our authors.
Two days after Valentine's on February 16, Riley and I will be celebrating
our 5th wedding anniversary. In fact, we're celebrating all weekend --
a long one with the holiday -- by leaving town and telling no one where we
are going. Riley is a very special guy, and we've had a great 5 years. I
look forward to many more with him.
February 16 is also the birthday of my nephew Alex Carter. He's 14 and
working on his Black Belt in Tae Kwon Do. He's a smart kid and loves
playing on his computer. I need to find the time to introduce him to Linux.
On a professional note, I am now Managing Editor of Linux Journal as well
as Linux Gazette. Gary Moore and I have switched jobs--keeps things from
getting boring. However, I refused to give up custody of Linux Gazette,
it's just too much fun.
Have fun!
_______________________________________________________________________________________________
Marjorie L. Richardson
Editor, Linux Gazette gazette@ssc.com
_______________________________________________________________________________________________
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