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<H4 ALIGN="center">
"Linux Gazette...<I>making Linux just a little more <FONT COLOR="red">lovable!</FONT></I>"
<IMG ALT="" SRC="../gx/adam/heart.png" WIDTH="30" HEIGHT="25">
</H4>
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<H1 ALIGN=CENTER><FONT COLOR="maroon">The Weekend Mechanic</FONT></H1>
<H4 ALIGN=CENTER>By <A HREF="mailto:thomas_adam16@yahoo.com">Thomas
Adam</A></H4>
<P> <HR> <P>
<!--===================================================================-->
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<!-- ---------------- -->
<!-- Begin Content Listing -->
<!-- ---------------- -->
<H2>Table of Contents</H2>
<UL>
<LI><A HREF="#preamble">Welcome
to the August edition</A>
<LI><A HREF="#apache">A brief
introduction: Apache</A>
<LI><A HREF="#progupx">Program
Review: upx</A>
<LI><A HREF="#progbb">Program
Review: bb</A>
<LI><A HREF="#closing">Closing Time</A>
</UL>
<!-- -------------- -->
<!-- End Content Listing -->
<!-- --------------- -->
<HR>
<!-- ----------- -->
<!-- Begin Preamble -->
<!-- ----------- -->
<H2><A NAME="preamble"></A>Welcome to the August edition</H2>
<P>Hello there, dear readers. How have you all been? Not too busy I
trust. I on the other hand have been busy over the last month or so.
I have just completed my A-level exams, which I found to be quite
tiring. That was why I was unable to write the Weekend Mechanic last
month. For those of you who are currently doing, or are thinking of
taking A-levels, I would advise you that although they are good fun
they require lots of hard work.</P>
<P>As a result of completing my A-levels (these are university entry
exams) I have also left school. Although for me this is rather sad,
it does mean that I shall have lots of time to develop my Linux
ideas. Thus, over the holidays I am hopefully going to be teaching
an evening class about using Linux. It is something that I am looking
forward to.</P>
<P>But I don't wish to delve too much into the future. Going back to
the world of computing one thing that happened recently which I
found quite amusing was that a young computer cracker (age 19
years, whose name I cannot remember) from Wales (UK), had gotten
a load of credit-card details and posted them onto another website.
Amongst the credit-card details obtained was that of Bill Gates. This
young cracker then used his credit-card, ordered a consignment of
viagra, and sent it to Bill Gates!!!</P>
<P>You'd have thought that the Welshman would have had something
better to do.........</P>
<!-- ---------- -->
<!-- End Preamble -->
<!-- ---------- -->
<HR>
<!-- ------------------->
<!-- Begin Apache -->
<!-- Begin Content Listing -->
<!-- ---------------- --->
<H2><A NAME="apache"></A>A Brief Introduction: Apache</H2>
<UL>
<LI><A HREF="#aboutinst">Installation</A>
<LI><A HREF="#runapache">Running
Apache</A>
<LI><A HREF="#configlochost">Using
Apache: http://localhost</A>
<LI><A HREF="#configpublic">Using
Apache: per-user webspaces</A>
<LI><A HREF="#configalias">Using
Apache: Aliases</A>
<LI><A HREF="#configsecure">Using Apache: Secure
Directories</A>
</UL>
<!-- -------------- -->
<!-- End Content Listing -->
<!-- -------------- --->
<HR>
<!-- ------------- -->
<!-- Begin Installation -->
<!-- ------------- -->
<H2><A NAME="aboutinst"></A>Installation</H2>
<P>The internet is growing at an alarming rate. Indeed, with nearly
every ISP there is the opportunity of being able to publish your own
web pages. The ability to do this is through the use of a computer
(the host), and a webserver program such as Apache. Although there
are other webservers, Apache is the most widely used on the internet
and is the most stable.</P>
<P>&quot;But why would you want to use it on a local machine?&quot;,
I hear you cry. Well running the Apache httpd daemon on your Linux
box means that it is a great way of storing information, especially
if you have a lot of HTML pages. I happen to have Apache running
because I have a local copy of all the LDP Howto's, and of course a
copy of the <I>Linux Gazette</I> archives!!</P>
<P>So the first thing to do is to test whether or not you have
Apache installed. If you are using a distribution that uses the RPM
file format, type in the following:</P>
<PRE>rpm -qa | grep -i apache</PRE>
<P>If successful you should see a line similar to:</P>
<PRE>apache-1.3.12-95</PRE>
<P>This means that the Apache webserver has been installed. If you do
not have Apache on your system then you must install it. Many
distributions come with Apache so the chances are it is on
your distribuion CD. If it is not, or your distribution does not
support the rpm format, then you must download the source files in
tarred/gzipped format (*.tar.gz) available from <A HREF="http://www.apache.org/" TARGET="_blank">www.apache.org</A>.
Once you have downloaded the files you can usually install apache in
the following way:</P>
<P>1. Log in as Root</P>
<P>2. Gunzip/untar the file:</P>
<PRE>tar xzvf /path/to/tarfile/apache*.tar.gz</PRE>
<P>3. cd to the newly created Apache directory:</P>
<PRE>cd Apache*</PRE>
<P>4. Run the &quot;configure&quot; script:</P>
<PRE>./configure</PRE>
<P>5. That will take a minute. Hopefully, that should be successful, and
a makefile, called &quot;Makefile&quot; should exist in the
directory. If not, it is likely that you do not have any compiler
programs (such as C, C++, g++), or you header files, or kernel source
files installed. It might also be possible that your make utility is
not installed. If this is true then you must install them.</P>
<P>So once configure has finished the thing you have to do now is
to &quot;make&quot; the file, by typing in the following:</P>
<PRE>make</PRE>
<P>This step may take some time, especially if you have an old machine.</P>
<P>Assuming there were no errors from the make, the last thing you have to do
is to install the compiled files by typing:</P>
<PRE>make install</PRE>
<P>And hopefully that should have installed Apache. If you do encounter
errors while installing/compiling Apache read the documentation that
comes with it. One caveat that I will mention is that during the
&quot;make&quot; process it is normal for the information to be
echoed to the screen. If you find that you are getting repeated
errors while compiling Apache, one work around is to issue the
following command:</P>
<PRE>make -k all</PRE>
<P>The above command will force make to continue, even
if it encounters errors <I>en route</I>. Although I only recommend
using it as an absolute last resort. Invariably reading Apache's
documentation should solve most compiler issues.</P>
<!-- End Installation Section -->
<!-- --------------------- -->
<!-- Begin Running Apache -->
<H2><A NAME="runapache"></A>Running Apache</H2>
<P>Now that everything has been installed the next thing to do is to
start Apache. This is accomplished by starting the &quot;httpd&quot;
daemon. By default (or at least for me anyway) Apache is
automatically run during your run-level so if you have not already
rebooted your machine type what follows still as user &quot;root&quot;:</P>
<PRE>httpd</PRE>
<P>Hopefully your prompt should have been returned with nothing echoed
to the screen. To check that the &quot;httpd&quot; daemon is running,
we can use our old friend &quot;ps&quot;, thus:</P>
<PRE>ps aux | grep -i httpd</PRE>
<P>What the above command does, is to list all the processes (including
those that are not attached to a tty), and then filters the list
(pipes &quot;|&quot;) it to the <I>grep</I> command, which will match
for the expression &quot;apache&quot;. The switch <B>-i</B> ignores
case sensitivity.</P>
<P>You should see a number of lines, but one which looks similar to
the following:</P>
<PRE>wwwrun 1377 0.0 2.0 4132 1340 ? S 11:09 0:00 httpd</PRE>
<P>This means that Apache is up and running. If you find that the result
of that command simply returns &quot;root blah blah <I>grep -i httpd</I>&quot;
then you must run httpd again. If you keep getting the same message, switch to <I>init 6</I></P>
<!-- End Running Apache -->
<! -- ------------------ -->
<!-- Begin Using Apache: http://localhost/ -->
<H2><A NAME="configlochost">Using Apache: http://localhost/</A></H2>
<P>OK, now were are getting somewhere. Having ensured that the
&quot;httpd&quot; daemon is active, we can actually start playing
with it. Open up a copy of a Web browser (such as Netscape) and
enter the following URL:</P>
<PRE>http://localhost</PRE>
<P>Hopefully you should see a web page of sorts. This usually differs
between different Linux distributions. On my SuSE box I am presented
with the SuSE Support Database with the SuSE chameleon mascot in the
top middle of the page!</P>
<P>The page that you are looking at is the main page at the site
&quot;localhost&quot;. This page is stored in the following
directory:</P>
<PRE>/usr/local/httpd/htdocs</PRE>
<P>This directory has a special name. It is called <B><I>DocumentRoot</I></B>.The
actual path may vary slightly on some systems, but invariably it is
similar to the above. In this directory you should notice some
files, in particular *.html files. The file that is loaded when you go
to &quot;http://localhost/&quot; is the file <I>index.html</I>. What
I have done, is created a sub-directory in &quot;htdocs&quot; called
&quot;oldhtdocs&quot;, and copied all the files into it. That way, I
can start afresh, and know that I have the originals if I need them.</P>
<P>You may find, that reading and writing to the <B>DocumentRoot</B>
folder has been disallowed to non-root users. To get around this
issue the following command as root, replacing &quot;/path/to/htdocs&quot;
with the correct pathway:</P>
<PRE>chmod +rw /path/to/htdocs</PRE>
<P>Knowing now, where the files are located for &quot;http://localhost/&quot;
is all very well, but how do you configure apache? Hang on there
reader......the file you are looking for is called <I>httpd.conf</I>
and is located usually in &quot;/etc/httpd&quot; or it maybe in the
directory &quot;/usr/local/apache&quot;. On SuSE and Mandrake
systems, the latter is the default place. In the sections that
follow I shall be using the &quot;httpd.conf&quot; file to carry out
various customisations.</P>
<!-- End Using Apache: http://localhost/ -->
<!-- --------------------------- -->
<!-- Begin Using Apache: Per-user web space -->
<H2><A NAME="configpublic"></A>Using Apache: Per-user webspace</H2>
<P>How many of you have gone to URL's that contain the tilde symbol
(~) followed by a name and then a (/)? I would imagine that nearly
everyone has, at sometime. But how many of you were aware of
what it meant?? The tilde symbol within a URL indicates a &quot;subdomain&quot;
that is owned by a user on the computer system, off the main domain name.
Thus, at school, I had my own webserver, with a valid URL:</P>
<PRE>http://linuxservertom.purbeck.dorset.local/~thomas_adam/</PRE>
<P>What this was doing, was actually retrieving files stored in a
special folder under the user account, of user &quot;thomas_adam&quot;.
This ability, gives users on a network, a space on which to house
their own web pages. So how is all this achieved? Well, it is quite
simple really....</P>
<P>All users, who are allowed their own webspace, have to be put in
the group <I>nogroup</I> (or <I>www-data</I> under Debian, etc). This can be
done, by editing the file &quot;/etc/group&quot; (as root), and locating the
line for &quot;nogroup&quot;. Then at the end of the line, add the users' name
separated by a comma. Then save the file.</P>
<P>In a user's home directory, a directory called <B><I>public_html</I></B>
has to be created, thus (as user root type):</P>
<PRE>cd /home/auser/ &amp;&amp; mkdir public_html</PRE>
<P>Where &quot;auser&quot; is the name of a valid user on the system.
Then the permissions have to be set. This is done by typing in the
following:</P>
<PRE>chmod 755 /home/auser/public_html</PRE>
<P>Then the last thing to do, is to set the group of that newly created
folder to <I>nogroup</I>. This can be done, by typing:</P>
<PRE>chown auser.nogroup /home/auser/public_html</PRE>
<P>Where &quot;auser&quot; is the name of the valid user.....substitute
as appropriate. The same procedure can be applied to all users. It
might also be an idea to play about with &quot;useradd&quot; so
that when you add new users, the &quot;public_html&quot; directory
with the permissions are set automatically.</P>
<P><I> [Actually, you don't <EM>have</EM> to do all that user and group
stuff, if you instead make sure the <I>public_html</I> directory and
all its files are world readable:
<PRE>chmod -R a+r /home/auser/public_html</PRE>
The important thing is that Apache has read access to the files. -- Mike Orr]
</I></P>
<P>So the next thing to do, is to make sure that Apache is aware of
what we have done. Open up the &quot;httpd.conf&quot; file, and lets
take a look......</P>
<P>By default, I think that the configuration that tells the Apache
about the public_html directive is commented out, or at least it was
in mine. From the beginning of the document, search for the keyword
<B>UserDir</B>. You should find something that looks like the
following:</P>
<PRE>&lt;IfModule mod_userdir.c&gt;
UserDir public_html
&lt;/IfModule&gt;
</PRE>
<P>If any of the above lines have a hash (#) symbol preceeding them,
delete them. The above lines tell Apache that the directory
&quot;public_html&quot; is to be used for html files for each user.</P>
<P>Directly below this are more related lines that tell apache what sort of
restrictions to apply. In the case of the following lines they are read-only.
If any of these are commented out, uncomment them.</P>
<PRE>&lt;Directory /home/*/public_html&gt;
AllowOverride FileInfo AuthConfig Limit
Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
&lt;Limit GET POST OPTIONS PROPFIND&gt;
Order allow,deny
Allow from all
&lt;/Limit&gt;
&lt;LimitExcept GET POST OPTIONS PROPFIND&gt;
Order deny,allow
Deny from all
&lt;/LimitExcept&gt;
&lt;/Directory&gt;</PRE>
<P>So now all that remains is to start to write the web pages. The only
other thing which you will find extremely useful is that if you
noticed my example earlier:</P>
<PRE>http://linuxservertom.purbeck.dorset.local/thomas_adam/</PRE>
<P>I had not specified a &quot;.html&quot; file to load. This is because
I had already told Apache a default file to look for within it. Such
a file is known as a <B>DirectoryIndex</B>, and you can specify
default files to load. Locate the following in your &quot;httpd.conf&quot;
file:</P>
<PRE>&lt;IfModule mod_dir.c&gt;
DirectoryIndex index.html index.shtml lwm.html home.html
&lt;/IfModule&gt;</PRE>
<P>What this is telling Apache is that when a URL is specified, such as
the example above, with no extension file after it (*.htm*), then it
will look for a default file(s) specified after the flag
&quot;DirectoryIndex&quot;. Thus in your &quot;public_html&quot;
file, if there was a file called &quot;index.html&quot;, then this
would be loaded on default. You are able to specify multiple files
as in my example above. If Apache cannot find anyone of the above
files then the directory listing is displayed instead (unless you specify
a file to load).</P>
<P>One thing that I would like to mention at this point, is if you
have specified a hostname in &quot;/etc/hosts&quot;, you can
substitute that name in place of &quot;http://localhost&quot;. It is
for convienience that I use it here. Furthermore in &quot;httpd.conf&quot;,
I would recommend that you find the following flag and substitute
<I>localhost</I> for the first part of your host name:</P>
<PRE>ServerName grangedairy</PRE>
<P>Thus my host name is <I>grangedairy.laptop</I>, I have simply put
<I>grangedairy</I>. The reasons for doing this will become apparant
from reading the <A HREF="#configalias">Alias Section</A></P>
<P>The last thing you have to do is with any changes that you make
to &quot;httpd.conf&quot;, you have to stop and restart it. This can
be achieved by typing in the following (as root):</P>
<PRE>
killall httpd
httpd
</PRE>
<!-- End per-user web space -->
<!-- ------------------- -->
<!-- Begin config-alias -->
<H2><A NAME="configalias"></A>Using Apache: Aliases</H2>
<P>In this section, I shall be covering the rather short topic of
<I>Aliases</I>. Using the &quot;httpd.conf&quot; file, we can see a
list of aliases if we search for the keyword &quot;alias&quot;.
Hopefully you should see a list which looks similar to the
following:</P>
<PRE>Alias /howto /usr/share/doc/howto/en/html/
Alias /mini /usr/share/doc/howto/en/html/mini/
Alias /lg /usr/share/doc/lg/
Alias /hilfe /usr/share/doc/susehilf/
Alias /doc /usr/share/doc/
Alias /cgi-bin-sdb /usr/local/httpd/cgi-bin/
Alias /sdb /usr/share/doc/sdb/
Alias /manual /usr/share/doc/packages/apache/manual/
Alias /htdig /opt/www/htdocs/htdig/
Alias /opt/kde/share/doc/HTML /opt/kde/share/doc/HTML/
Alias /opt/gnome/share/gnome/help/ /opt/gnome/share/gnome/help/
Alias /errors/ /usr/local/httpd/errors/
Alias /icons/ /usr/local/httpd/icons/
Alias /admin /usr/local/httpd/admin/
Alias /lwm /usr/share/doc/lg/lwm/</PRE>
<P>As you can see, what the above is saying, is that if the URL ends in
a &quot;/howto&quot; for example, then Apache is to get its web pages
from the directory &quot;/usr/share/doc/howto/en/html&quot;. Once
again the default web page that it will load up is taken from
<I>DirectoryIndex</I>, as we saw earlier.</P>
<PRE>http://grangedairy/howto</PRE>
<P>You may remember that earlier I had said that you should specify a
<I>ServerName</I> flag in &quot;httpd.conf&quot;. This was done so
that when you typed in the URL with one of the above aliases, you do
not need to put an extra forward slash at the end of the URL. You
see, originally, the above aliases, were alised thus:</P>
<PRE>Alias /howto/ /usr/share/doc/howto/en/html/
Alias /mini/ /usr/share/doc/howto/en/html/mini/</PRE>
<P>with extra forward slashes after the alias name. I soon got tired of
having to add this in myself and so I was able to tell Apache how to
do this for me. By setting the <I>ServerName</I> flag apache now
knows the name of my machine so that when I go to:</P>
<PRE>http://grangedairy/howto</PRE>
<P>It automatically appends the forward slash at the end. Cool, eh?? So
if you have done the same as me you can delete the trailing forward
slashes from the alias name because hopefully, you should not need
them!</P>
<!-- End config-alias -->
<! -- ---------------- -->
<!-- Begin Secure-directories -->
<H2><A NAME="configsecure"></A>Using Apache: Secure Directories</H2>
<P>The final part to my Apache tutorial is how to set up and create
&quot;secure directories&quot;, i.e. those that require user
authentication before they are loaded. You will have noticed earlier
that in my listing examples of <I>Aliases</I>, there was one for
&quot;/admin&quot;. This is in fact a secure directory.</P>
<P>You can set up secure directories in the same way that you would an
ordinary alias except this time, you have to tell Apache a little
bit about the directory itself and how it is to be parsed. So say
that you wanted to set up a secure directory <B><I>mysecuredir</I></B>,
at location &quot;/usr/local/httpd/mysecuredir/&quot; You would do
the following:</P>
<P>1. Add &quot;/mysecuredir&quot; to alias list:</P>
<PRE>alias /mysecuredir /usr/local/httpd/mysecuredir</PRE>
<P>2. Change to the location of the folder that you have specified in the <I>
alias</I> list, thus:</P>
<PRE>cd /usr/local/httpd</PRE>
<P>3. Create the directory &quot;mysecuredir&quot; by typing in:</P>
<PRE>mkdir mysecuredir && cd mysecuredir</PRE>
<P>This has created the directory, and changed to it.</P>
<P>4. Now the work begins. There are two files that we shall be using .htaccess
and htpasswd. The first file (.htaccess) is the one that we shall set up first. It is
this file that will store the information about how the &quot;mysecuredir&quot; is
to be used.</P>
<P>So at the console, use an editor such as <I>nano (a pico clone), jed, emacs,</I>
etc, to create the .htaccess file, and enter the following information, exactly as shown
because apache is case-sensitive in parsing commands!:</P>
<PRE>
AuthType Basic
AuthName "Restricted Directory"
AuthUserFile /usr/local/httpd/admin/htpasswd
require valid-user
</PRE>
<P> (Since ,htaccess starts with a period, it won't show up in
ordinary directory listings. Use "ls -a" to see it.)
<P>The commands above are the most common ones used to create a secure directory.
The table below will give a short description of the commands and how you can customise
them.<P>
<TABLE BORDER=2 WIDTH=100%>
<TBODY>
<TH>Option Tag</TH>
<TH>Meaning</TH>
<TR>
<TD WIDTH=25% ALIGN="middle"><B>AuthType</B></TD>
<TD ALIGN="left">This sets the authentication type. Basic is usally always used.</TD>
</TR>
<TR>
<TD WIDTH=25% ALIGN="middle"><B>AuthName</B></TD>
<TD ALIGN="left">Sets the name on the "login" box of the directory that you are
trying to connect to (see the screenshot below).</TD>
</TR>
<TR>
<TD WIDTH=25% ALIGN="middle"><B>AuthUserFile</B></TD>
<TD ALIGN="left">This is the file that is used to check for authentication, i.e. it
stores your username and password (encrypted of course). You must ensure
that you use the full path to the htpasswd file.</TD>
</TR>
<TR>
<TD WIDTH=25% ALIGN="middle"><B>require valid-user</B></TD>
<TD ALIGN="left">This says that access is only allowed to those who have a valid entry
in the htpasswd file.</TD>
</TR>
</TBODY>
</TABLE>
<P> Note: for additional security, put the htpasswd file somewhere that is
<EM>not</EM> accessible via URL--somewhere outside your web directory and
outside your alias directories. A .htaccess file must be in the URL-accessible
directory it's protecting, but the htpasswd file may be anywhere.
You may also share the same htpasswd file among several .htaccess directories
if desired.
<P>Ok, now that we have told apache how to handle the directory we now need to create the password file:</P>
<P>5. To create the <I>htpasswd</I> file you have to type in the following command (in the same directory
as the &quot;.htaccess&quot; file:</P>
<PRE>htpasswd -c htpasswd username</PRE>
<P>Whereby you replace &quot;username&quot; with your username. To keep adding users to the file, issue the same command, but remove the &quot;-c&quot; flag.</P>
<P>6. Now edit our friend <I>/etc/httpd/httpd.conf</I> and at the bottom of the alias list, add the following:</P>
<PRE>
&lt;Directory /usr/local/httpd/*&gt;
AllowOverride AuthConfig
&lt;/Directory&gt;
</PRE>
<P>You may have to modify it slightly, but that will ensure that if apache meets any &quot;.ht*&quot; files
it will use them to apply security on them. To turn off this, for the above, change <I>AllowOverride AuthConfig</I>
to <I>AllowOverride None</I>.</P>
<P>Now stop and restart the <I>httpd</I> daemon</P>
<P>Ok now you are all set to try it out. Having saved the files go to your web browser and type in the following:</P>
<PRE>http://servername/mysecuredir</PRE>
<P>Making sure that you replace &quot;servername&quot; with either your hostname, or &quot;localhost&quot;.
If successful you should see a dialog box similar to
<A HREF="misc/adam/screenshot.jpg">this screenshot</A>.</P>
<P>Once you have entered the correct details you should then be off and away. You may find however that
you can connect to the &quot;mysecure&quot; directory without having to supply any credentials. If this happens,
you need to check the following in your &quot;/etc/httpd/httpd.conf&quot; file.....
<P>It may be that apache has not been configured to recognise the use of &quot;.ht*&quot; files.
You can tell Apache to undo this, by setting the <I>AccessFileName</I> tag, thus:</P>
<I>AccessFileName .htaccess</I>
<P>Well, that concludes this entire section. I did consider writing a few words about the use of perl and cgi, but I
decided that Mark Nielsen has done a better job over the last few months. Furthermore, Ben Opoknik has been
creating yet another excellent tutorial, this time on Perl, so if you are interested in cgi programming,
I would start by reading these two series of articles :-)</P>
<!-- ------------------------- -->
<!-- End Secure-directories -->
<!-- End A brief introduction: Apache -->
<!-- --------------------------- -->
<HR>
<!-- -------------------------- -->
<!-- Begin PR: upx -->
<! -- -------------------------- -->
<H2><A NAME="progupx"></A>Program Review: Upx</H2>
<P>I stumbled across this program quite by accident. I was originally doing some research at school for the
acting network administrator (hi Dave!) which involved the use of power management, as we were having
some problems with monitors "sleeping (room D25)" but I digress.....</P>
<P>UPX (Ultimate Packer for eXecutables) is a compression program. What this program actually does, is
compress binary executable files which are self contained, and which do not slow down execution or memory
performance. A typical use for this type of program is best suited to laptop users, where harddrive space is of
enormous concern. Since I use my laptop for most things and only have a 3.2GB harddrive, I have found that
compressing the files stored in <CODE>&quot;/usr/bin&quot;</CODE> has cut the size of that directory in half!</P>
<P>Since it will only compress binary files, it is no good trying to compress the files stored in &quot;/etc&quot; for
example. I have found that compressing the following directories is ok:</P>
<PRE>
/usr/bin
/usr/X11R6/bin
/usr/local/bin
</PRE>
<FONT COLOR="red">
<P>One caveat that I should mention, is that I would NEVER use &quot;upx&quot; to compress the files stored in
both <B>&quot;/bin&quot;</B> and <B>&quot;/usr/sbin&quot;</B> When I rebooted my computer, I found that Init would
not run. Out came &quot;Tom's root/boot&quot; and I later discovered that the compression of these files was causing
the main Init program problems for some reason........</P>
</FONT>
<P>So to use the program, download the package from <A HREF="http://wildsau.idv.uni-linz.ac.at/mfx/upx.html" TARGET="_blank">
http://wildsau.idv.uni-linz.ac.at/mfx/upx.html</A>. I think you have the choice of either downloading the source
packages, or a pre-compiled executable.</P>
<P>I simply downloaded the pre-compiled package, unpacked it, and copied the main upx program to &quot;/usr/bin&quot;.
then you are ready to start compressing files.</P>
<P>To compress a file, you have to type in the following:</P>
<PRE>upx /path/to/program/progname</PRE>
<P>and that will compress the program specified. You can also compress all files in the directory, by typing:</P>
<PRE>upx /path/to/programs/*</PRE>
<P>and UPX will happily go through all files, and instantly disregard those which are not Linux/386 format.</P>
<P>Here's a <A HREF="misc/adam/shupx.png">screenshot</A>
of UPX in action.</P>
<P>To decompress files, you have to use the &quot;-d&quot; flag, thus:</P>
<PRE>upx -d /path/to/prog/*</PRE>
<P>A common list of command-line options, are:</P>
<PRE>
Usage: upx [-123456789dlthVL] [-qvfk] [-o file] file..
Commands:
-1 compress faster -9 compress better
--best compress best (can be very slow for big files)
-d decompress -l list compressed file
-t test compressed file -V display version number
-h give this help -L display software license
Options:
-q be quiet -v be verbose
-oFILE write output to `FILE'
-f force compression of suspicious files
--no-color, --mono, --color, --no-progress change look
Backup options:
-k, --backup keep backup files
--no-backup no backup files [default]
Overlay options:
--overlay=copy copy any extra data attached to the file [default]
--overlay=strip strip any extra data attached to the file [dangerous]
--overlay=skip don't compress a file with an overlay
</PRE>
<P>Overall, the performance of the compressed files have been ok, and I have not noticed any loss in functionality.
The only program that did take a long time to load up once it had been compressed was <B>netscape</B> but that
did not bother me too much (netscape uses so much memory, I am used to waiting for it to load).</P>
<!-- -------------------------- -->
<!-- End PR: upx -->
<! -- -------------------------- -->
<HR>
<!-- -------------------------- -->
<!-- Begin PR: bb -->
<! -- -------------------------- -->
<H2><A NAME="progbb"></A>Program Review: bb</H2>
<P>In issue 67 of the Linux Gazette, Mike Orr,
<A HREF="../issue67/orr.html">reviewed</A> <B>cowsay/cowthink</B>, a
configurable talking cow that
displays messages in speech bubbles. Everything is written in Perl (my
second-favourite scripting language, after
bash) and is displayed in ASCII. I was so impressed with the cows that I decided to look for more ASCII programs. Out came my SuSE distribution CD's and I found the program <B>bb</B>.......</P>
<P><B>bb</B> is a fully-working ASCII demo,
which uses ANSI C and is SVGA compatible. <B>bb</B> makes use of the
aa_lib package (ASCII art library) so you will have to install it along with
the main package. The demo produces a range of different simulated pictures,
from random tumbling characters (going through different shades of grey), to an
ASCII simulated mandlebrot fractual!! (which incidentially inspired the colour
version of <B>Xaos</B>). </P>
<P>You can get <B>bb</B> from
<A HREF="ftp://ftp.bonn.linux.de/pub/misc/bb-1.2.tar.gz">
ftp://ftp.bonn.linux.de/pub/misc/bb-1.2.tar.gz</A>.</P>
<P> <B>bb</B> used to have
a home page, but unfortunately it's gone. However, project <B>aa</B>
(the ASCII Art library) is what <B>bb</B> is based on, and it has a home
page at
<A HREF="http://aa-project.sourceforge.net/">http://aa-project.sourceforge.net/</A>.
The <B>aa</B> page also discusses <B>aview</B> (an ASCII art viewer),
<B>aatv</B> (to view TV programs on your text console), <B>ttyquake</B>
(a text version of Quake), <B>Dumb</B> (a Doom clone), <B>apron</B> (an
mpeg1 player), and other programs. <B>ttyquake</B> does require the
graphical Quake to be installed, so it uses the original Quake game
files. One commentator writes of <b>ttyquake</B>, "people are starving to
death in this world... and somebody had time for this....."
<P><B>bb</B> is best run from the console, but it can be run from within an
X-terminal window, as shown by <A HREF="misc/adam/bbscreenshot.png">this
screenshot</A>.</P>
<P>The valid command-line options for <B>bb</B> are:</P>
<PRE>
Usage: bb [aaoptions] [number]
Options:
-loop play demo in infinite loop
AAlib options:
-driver select driver
available drivers:linux curses X11 stdout stderr
-kbddriver select keyboard driver
available drivers:curses X11 stdin
-mousedriver select mouse driver
available drivers:X11 gpm cursesdos
Size options:
-width set width
-height set height
-minwidth set minimal width
-minheight set minimal height
-maxwidth set maximal width
-maxheight set maximal height
-recwidth set recomended width
-recheight set recomended height
Attributes:
-dim enable usage of dim (half bright) attribute
-bold enable usage of bold (double bright) attribute
-reverse enable usage of reverse attribute
-normal enable usage of normal attribute
-boldfont enable usage of boldfont attrubute
-no&lt;attr&gt; disable (i.e -nobold)
Font rendering options:
-extended use all 256 characters
-eight use eight bit ascii
-font &lt;font&gt; select font(This option have effect just on hardwares
where aalib is unable to determine current font
available fonts:vga8 vga9 mda14 vga14 X8x13 X8x16
X8x13bold vgagl8 line
Rendering options:
-inverse enable inverse rendering
-noinverse disable inverse rendering
-bright &lt;val&gt; set bright (0-255)
-contrast &lt;val&gt; set contrast (0-255)
-gamma %lt;val&gt; set gamma correction value(0-1)
Ditherng options:
-nodither disable dithering
-floyd_steinberg floyd steinberg dithering
-error_distribution error distribution dithering
-random &lt;val&gt; set random dithering value(0-inf)
Monitor parameters:
-dimmul &lt;val&gt; multiply factor for dim color (5.3)
-boldmul &lt;val&gt; multiply factor for dim color (2.7)
The default parameters are set to fit my monitor (15" goldstar)
With contrast set to maximum and bright set to make black black
This values depends at quality of your monitor (and setting of controls
Defaultd settings should be OK for most PC monitors. But ideal monitor
Needs dimmul=1.71 boldmul=1.43. For example monitor used by SGI is very
close to this values. Also old 14" vga monitors needs higher values.
</PRE>
<P>I really do think that if you're into ASCII art, you should give this demo a
go. It lasts for approximately 5 minutes.</P>
<!-- -------------------------- -->
<!-- End PR: bb -->
<! -- -------------------------- -->
<HR>
<!-- -------------------------- -->
<!-- Begin Closing Time -->
<! -- -------------------------- -->
<H2><A NAME="closing">Closing Time</A></H2>
<P>Well, you've made it to the end of this months article. Looking ahead to next month, I am going to be writing an
article about how to write efficient manual pages (anyone remember groff processing??) and whatever else I can think of.
However it would be nice to hear from anyone who has article suggestions, as I am running out of ideas.....slowly. If there
is anything you feel would be good to include in the LWM, drop me a note :-)</P>
<P>Also, in case anyone is interested, all the screenshots that have appeared in this document, have been using made using
the &quot;GNU Image Manipulation Program&quot; and are of the <B>FVWM2</B> window manager, running the M4 preprocessor <B>AnotherLevel</B>.
<P>As a final notice, I would like to say that as I am no longer at school anymore, my &quot;n6tadam@users.purbeck.
dorset.sch.uk&quot; account is invalid, and I now have a new account (see below).</P>
<P>So until next time....<B>happy linuxing!</B></P>
<!-- -------------------------- -->
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<TD WIDTH=10%><IMG ALT="" SRC="../gx/adam/mail.png" ALIGN="left" WIDTH="64" HEIGHT="64"></TD>
<TD WIDTH=80% ALIGN="center"><FONT COLOR="red" SIZE="5">Send Your Comments</FONT></TD>
<TD WIDTH=10%><IMG ALT="" SRC="../gx/adam/mail.png" ALIGN="left" WIDTH="64" HEIGHT="64"></TD>
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<P ALIGN="center"><FONT SIZE="3">Any comments, suggestions, ideas, etc can be
mailed to me by clicking the e-mail address link below:</FONT></P>
<P ALIGN="center"><FONT SIZE="3"><A
HREF="mailto:thomas_adam16@yahoo.com">&lt;thomas_adam16@yahoo.com&gt;</A></FONT></P>
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<H5 align=center>Copyright <20> 2001, Thomas Adam.<BR>Copying license <A
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<BR>
Published in Issue 70 of <I>Linux Gazette</I>, September 2001
</H5>
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<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Thomas Adam</H4>
<EM>My name is Thomas Adam. I am 18, and am currently studying for A-Levels
(=university entrance exam). I live
on a small farm, in the county of Dorset in England. I am a massive Linux
enthusiast, and help with linux proxy issues while I am at school. I have been
using Linux now for about six years. When not using Linux, I play the piano,
and enjoy walking and cycling.</EM>
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Copyright &copy; 2001, Thomas Adam.<BR>
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 70 of <i>Linux Gazette</i>, September 2001</H5>
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