1414 lines
22 KiB
HTML
1414 lines
22 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<HTML
|
|
><HEAD
|
|
><TITLE
|
|
>Tips And Tricks</TITLE
|
|
><META
|
|
NAME="GENERATOR"
|
|
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
|
|
REL="HOME"
|
|
TITLE="The Linux FAQ"
|
|
HREF="index.html"><LINK
|
|
REL="PREVIOUS"
|
|
TITLE="Solutions to Common Problems"
|
|
HREF="common-problems.html"><LINK
|
|
REL="NEXT"
|
|
TITLE="The X Window System"
|
|
HREF="x-windows.html"></HEAD
|
|
><BODY
|
|
CLASS="sect1"
|
|
BGCOLOR="#FFFFFF"
|
|
TEXT="#000000"
|
|
LINK="#0000FF"
|
|
VLINK="#840084"
|
|
ALINK="#0000FF"
|
|
><DIV
|
|
CLASS="NAVHEADER"
|
|
><TABLE
|
|
SUMMARY="Header navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TH
|
|
COLSPAN="3"
|
|
ALIGN="center"
|
|
>The Linux FAQ</TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="left"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="common-problems.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="80%"
|
|
ALIGN="center"
|
|
VALIGN="bottom"
|
|
></TD
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="right"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="x-windows.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"></DIV
|
|
><DIV
|
|
CLASS="sect1"
|
|
><H1
|
|
CLASS="sect1"
|
|
><A
|
|
NAME="tips"
|
|
></A
|
|
>15. Tips And Tricks</H1
|
|
><DIV
|
|
CLASS="qandaset"
|
|
><DL
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#man-pages-without-man"
|
|
>How Do I Format Man Pages without <B
|
|
CLASS="command"
|
|
>man</B
|
|
> or <B
|
|
CLASS="command"
|
|
>groff</B
|
|
>?</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#scrollback-in-text-mode"
|
|
>How To Scroll Backwards in Text Mode</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#e-mail-to-work"
|
|
>How To Get Email to Work</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#sendmail-pause"
|
|
><SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
> Pauses for Up to a Minute at Each Command</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#switch-virtual-consoles"
|
|
>How To Enable and Select Virtual Consoles</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#set-the-time-zone"
|
|
>How To Set the Time Zone</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#core-file"
|
|
>What Is a <TT
|
|
CLASS="filename"
|
|
>core</TT
|
|
> File?</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#enable-core-dumps"
|
|
>How To Enable or Disable Core Dumps</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#remap-keyboard"
|
|
>How To Remap a Keyboard to UK, French, Etc.</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#num-lock-default-on"
|
|
>How To Get NUM LOCK to Default to On</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#set-terminal-colors"
|
|
>How To Set (Or Reset) Initial Terminal Colors</A
|
|
></DT
|
|
><DT
|
|
>Q: <A
|
|
HREF="tips.html#more-than-128mb-of-swap"
|
|
>How To Have More Than 128Mb of Swap</A
|
|
></DT
|
|
></DL
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="man-pages-without-man"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How Do I Format Man Pages without <B
|
|
CLASS="command"
|
|
>man</B
|
|
> or <B
|
|
CLASS="command"
|
|
>groff</B
|
|
>?</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>The <B
|
|
CLASS="command"
|
|
>man2html</B
|
|
> program translates <B
|
|
CLASS="command"
|
|
>groff</B
|
|
>
|
|
text to HTML, which you can view with a Web browser. The
|
|
<B
|
|
CLASS="command"
|
|
>man2html</B
|
|
> program, and many like it, are availble on the
|
|
Web. Look for them with your favorite search engine.
|
|
</P
|
|
><P
|
|
>The unformatted manual pages are stored in subdirectories of
|
|
<TT
|
|
CLASS="filename"
|
|
>/usr/man</TT
|
|
>, <TT
|
|
CLASS="filename"
|
|
>/usr/local/man</TT
|
|
>, and
|
|
elsewhere.
|
|
</P
|
|
><P
|
|
>If you want to view text, use <B
|
|
CLASS="command"
|
|
>nroff</B
|
|
> and <B
|
|
CLASS="command"
|
|
>less</B
|
|
>.
|
|
Both of these programs have MSDOS versions with an implementation of the <EM
|
|
>man</EM
|
|
>
|
|
macro package available as well. An example would be:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> $ nroff -man /usr/man/man1/ls.1 | less </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
>If you know where to find a good implementation of the <EM
|
|
>man</EM
|
|
> macros
|
|
without installing <EM
|
|
>groff</EM
|
|
>, please let the FAQ maintainer
|
|
know.
|
|
</P
|
|
><P
|
|
>If the manual page filename ends in <TT
|
|
CLASS="literal"
|
|
>.gz</TT
|
|
>, then you'll need to
|
|
uncompress it before formatting it, using <B
|
|
CLASS="command"
|
|
>gzip -d</B
|
|
> or <B
|
|
CLASS="command"
|
|
>gunzip</B
|
|
>.
|
|
A one-line example would be:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> $ gzip -dc /usr/man/man1/ls.1.gz | nroff -man | less </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="scrollback-in-text-mode"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Scroll Backwards in Text Mode</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>With the default US keymap, you can
|
|
use <B
|
|
CLASS="keycap"
|
|
>Shift</B
|
|
> with the <B
|
|
CLASS="keycap"
|
|
>PgUp</B
|
|
> and
|
|
<B
|
|
CLASS="keycap"
|
|
>PgDn</B
|
|
> keys. (The gray ones, not the ones on the numeric
|
|
keypad.) With other keymaps, look in <TT
|
|
CLASS="filename"
|
|
>/usr/lib/keytables</TT
|
|
>.
|
|
You can remap the <B
|
|
CLASS="keycap"
|
|
>ScrollUp</B
|
|
> and <B
|
|
CLASS="keycap"
|
|
>ScrollDown</B
|
|
> keys to be whatever you like.
|
|
</P
|
|
><P
|
|
>The <B
|
|
CLASS="command"
|
|
>screen</B
|
|
> program, <A
|
|
HREF="http://vector.co.jp/vpack/browse/person/an010455.html"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>http://vector.co.jp/vpack/browse/person/an010455.html</I
|
|
></A
|
|
>
|
|
provides a searchable scrollback buffer and the ability to take
|
|
"snapshots" of text-mode screens.
|
|
</P
|
|
><P
|
|
>Recent kernels that have
|
|
the VGA Console driver can use dramatically more memory for scrollback,
|
|
provided that the video card can <EM
|
|
>actually handle</EM
|
|
> 64 kb
|
|
of video memory. Add the line:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> #define VGA_CAN_DO_64B </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
>to the start of the file <TT
|
|
CLASS="filename"
|
|
>drivers/video/vgacon.c</TT
|
|
>. This feature may become a
|
|
standard setting in future kernels. If the video frame buffer is also enabled
|
|
in the kernel, this setting may not affect buffering.
|
|
</P
|
|
><P
|
|
>In older kernels, the amount of scrollback is fixed, because it is implemented using
|
|
the video memory to store the scrollback text. You may be able to get more
|
|
scrollback in each virtual console by reducing the total number of VC's. See
|
|
<TT
|
|
CLASS="filename"
|
|
>linux/tty.h</TT
|
|
>.
|
|
</P
|
|
><P
|
|
>[Chris Karakas]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="e-mail-to-work"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Get Email to Work</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>For sending mail via SMTP (Simple Mail Transfer
|
|
Protocol) and receiving mail from an ISP's POP (Post Office Protocol) server,
|
|
you can use a desktop client like Netscape Communicator or KDE kmail. You
|
|
will need to enter the names of the SMTP and POP servers in the preferences
|
|
of the respective application, as well as your E-mail address
|
|
(e.g., username@example.com), and your dial-up password. The same applies to
|
|
Usenet News. Enter the name of the NNTP (Network News Transfer Protocol)
|
|
server in your News client's preferences section. You may also have to
|
|
provide the IP addresses of the ISP's primary and secondary name servers.
|
|
</P
|
|
><P
|
|
>If you have a traditional MTA (Mail Transport Agent) like
|
|
<SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
>, <SPAN
|
|
CLASS="application"
|
|
>Smail</SPAN
|
|
>,
|
|
<SPAN
|
|
CLASS="application"
|
|
>qmail</SPAN
|
|
>, or <SPAN
|
|
CLASS="application"
|
|
>Exim</SPAN
|
|
>, you'll
|
|
need to follow the instructions in each package. Basically, configuration
|
|
entails determining which host machine, either on your local LAN or via
|
|
dial-up Internet, is the "Smart Host", if you're using SMTP. If you're
|
|
using the older UUCP protocol, then you'll need to consult the directions for
|
|
configuring UUCP, and also make sure that your ISP's system is configured to
|
|
relay mail to you.
|
|
</P
|
|
><P
|
|
>Information about Internet hosting, and
|
|
News and E-mail in general, is available on the Usenet News group
|
|
<I
|
|
CLASS="citetitle"
|
|
>news.announce.newusers</I
|
|
>, and those FAQ's are also
|
|
archived at <A
|
|
HREF="ftp://rtfm.mit.edu/pub/usenet/"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>ftp://rtfm.mit.edu/pub/usenet/</I
|
|
></A
|
|
>.
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="sendmail-pause"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
><SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
> Pauses for Up to a Minute at Each Command</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>Make sure that <SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
>
|
|
can resolve your hostname to a valid (i.e., parsable) domain address. If you
|
|
are not connected to the Internet, or have a dial-up connection with dynamic
|
|
IP addressing, add the fully qualified domain name to the
|
|
<TT
|
|
CLASS="literal"
|
|
>/etc/hosts</TT
|
|
> file, <EM
|
|
>in addition</EM
|
|
> to the
|
|
base host name; e.g., if the host name is <TT
|
|
CLASS="literal"
|
|
>bilbo</TT
|
|
> and
|
|
the domain is <TT
|
|
CLASS="literal"
|
|
>bag-end.com</TT
|
|
>:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> 192.168.0.1 bilbo.bag-end.com bilbo </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
>And make sure that either the <TT
|
|
CLASS="literal"
|
|
>/etc/host.conf</TT
|
|
> or <TT
|
|
CLASS="literal"
|
|
> /etc/resolv.conf</TT
|
|
> file contains the line:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> order hosts,bind </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
><DIV
|
|
CLASS="caution"
|
|
><P
|
|
></P
|
|
><TABLE
|
|
CLASS="caution"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="25"
|
|
ALIGN="CENTER"
|
|
VALIGN="TOP"
|
|
><IMG
|
|
SRC="../images/caution.gif"
|
|
HSPACE="5"
|
|
ALT="Caution"></TD
|
|
><TD
|
|
ALIGN="LEFT"
|
|
VALIGN="TOP"
|
|
>Do not change the <TT
|
|
CLASS="literal"
|
|
>localhost</TT
|
|
>entry in
|
|
<TT
|
|
CLASS="literal"
|
|
>/etc/hosts</TT
|
|
>, because many programs depend on it for
|
|
internal message-passing.</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
>
|
|
</P
|
|
><P
|
|
><SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
>
|
|
takes many factors into account when resolving domain addresses. These
|
|
factors, collectively, are known as, "rulesets", in
|
|
<SPAN
|
|
CLASS="application"
|
|
>sendmail</SPAN
|
|
> jargon. The program does
|
|
<EM
|
|
>not</EM
|
|
> require that a domain address be canonical, or even
|
|
appear to be canonical. In the example above, <TT
|
|
CLASS="literal"
|
|
>bilbo.</TT
|
|
>
|
|
(note the period) would work just as well as
|
|
<TT
|
|
CLASS="literal"
|
|
>bilbo.bag-end.com</TT
|
|
>. This and other modifications apply
|
|
mainly to recent versions.
|
|
</P
|
|
><P
|
|
>Prior to version 8.7,
|
|
<SPAN
|
|
CLASS="application"
|
|
>sendmail</SPAN
|
|
> required that the FQDN appear first in
|
|
the <TT
|
|
CLASS="filename"
|
|
>/etc/hosts</TT
|
|
> entry. This is due to changes in the
|
|
envelope address masquerade options. Consult the
|
|
<SPAN
|
|
CLASS="application"
|
|
>sendmail</SPAN
|
|
> documents.
|
|
</P
|
|
><P
|
|
>If you have a
|
|
domain name server for <EM
|
|
>only</EM
|
|
> a local subnet, make sure
|
|
that "." refers to a SOA record on the server machine, and that reverse
|
|
lookups (check by using <SPAN
|
|
CLASS="application"
|
|
>nslookup</SPAN
|
|
>) work for all
|
|
machines on the subnet.
|
|
</P
|
|
><P
|
|
>Finally, <TT
|
|
CLASS="literal"
|
|
>FEATURE</TT
|
|
>
|
|
configuration macro options like <TT
|
|
CLASS="literal"
|
|
>nodns</TT
|
|
>,
|
|
<TT
|
|
CLASS="literal"
|
|
>always_add_domain</TT
|
|
>, and <TT
|
|
CLASS="literal"
|
|
>nocanonify</TT
|
|
>,
|
|
control how <SPAN
|
|
CLASS="application"
|
|
>sendmail</SPAN
|
|
> interprets host names.
|
|
</P
|
|
><P
|
|
>The document, <I
|
|
CLASS="citetitle"
|
|
>Sendmail: Installation and Operation
|
|
Guide</I
|
|
>, included in the <TT
|
|
CLASS="literal"
|
|
>doc/</TT
|
|
> subdirectory of
|
|
<SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
> source code distributions, discusses
|
|
briefly how <SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
> resolves Internet addresses.
|
|
<SPAN
|
|
CLASS="application"
|
|
>Sendmail</SPAN
|
|
> source code archives are listed at:
|
|
<A
|
|
HREF="http://www.sendmail.org/"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>http://www.sendmail.org/</I
|
|
></A
|
|
>
|
|
</P
|
|
><P
|
|
>[Chris Karakas]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="switch-virtual-consoles"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Enable and Select Virtual Consoles</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>In text mode, press the left
|
|
<B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>F1</B
|
|
> to
|
|
<B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>F12</B
|
|
> to select the consoles
|
|
<TT
|
|
CLASS="literal"
|
|
>tty1</TT
|
|
> to <TT
|
|
CLASS="literal"
|
|
>tty12</TT
|
|
>; Right
|
|
<B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>F1</B
|
|
> gives
|
|
<TT
|
|
CLASS="literal"
|
|
>tty13</TT
|
|
> and so on. To switch out of X you must press
|
|
<B
|
|
CLASS="keycap"
|
|
>Ctrl</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>F1</B
|
|
>, etc;
|
|
<B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>-<B
|
|
CLASS="keycap"
|
|
>F5</B
|
|
> or whatever will switch back.
|
|
</P
|
|
><P
|
|
>However, If you have a non-PC compatible system, please see the note below.
|
|
</P
|
|
><P
|
|
>If you want to use a VC for ordinary login, it must be listed in
|
|
<I
|
|
CLASS="citetitle"
|
|
>/etc/inittab</I
|
|
>, which controls which terminals and
|
|
virtual consoles have login prompts. The X Window System needs at least one
|
|
free VC in order to start.
|
|
</P
|
|
><P
|
|
><DIV
|
|
CLASS="note"
|
|
><P
|
|
></P
|
|
><TABLE
|
|
CLASS="note"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="25"
|
|
ALIGN="CENTER"
|
|
VALIGN="TOP"
|
|
><IMG
|
|
SRC="../images/note.gif"
|
|
HSPACE="5"
|
|
ALT="Note"></TD
|
|
><TD
|
|
ALIGN="LEFT"
|
|
VALIGN="TOP"
|
|
>The key sequence is actually <B
|
|
CLASS="keycap"
|
|
>Ctrl</B
|
|
><TT
|
|
CLASS="literal"
|
|
>Meta</TT
|
|
><B
|
|
CLASS="keycap"
|
|
>F</B
|
|
><EM
|
|
>N</EM
|
|
>. On PC
|
|
compatible systems, the right and left <B
|
|
CLASS="keycap"
|
|
>Alt</B
|
|
>keys are really
|
|
synonymous with the keysymbols <TT
|
|
CLASS="literal"
|
|
>Meta_L</TT
|
|
>and
|
|
<TT
|
|
CLASS="literal"
|
|
>Meta_R</TT
|
|
>. If the binding is different, you can determine
|
|
what keys produce <TT
|
|
CLASS="literal"
|
|
>Meta_L</TT
|
|
>and <TT
|
|
CLASS="literal"
|
|
>Meta_R</TT
|
|
>with <SPAN
|
|
CLASS="application"
|
|
>xkeycaps</SPAN
|
|
>or a similar application.</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
>
|
|
</P
|
|
><P
|
|
>[David Charlap]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="set-the-time-zone"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Set the Time Zone</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>Change directory to <TT
|
|
CLASS="filename"
|
|
>/usr/lib/zoneinfo/</TT
|
|
>. Get the time zone package if you
|
|
don't have this directory. The source is available in
|
|
<A
|
|
HREF="ftp://metalab.unc.edu/pub/Linux/system/admin/time/"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>ftp://metalab.unc.edu/pub/Linux/system/admin/time/</I
|
|
></A
|
|
>.
|
|
</P
|
|
><P
|
|
>Then make a symbolic link named <TT
|
|
CLASS="filename"
|
|
>localtime</TT
|
|
>
|
|
pointing to one of the files in this directory (or a subdirectory), and one
|
|
called <TT
|
|
CLASS="filename"
|
|
>posixrules</TT
|
|
> pointing to
|
|
<TT
|
|
CLASS="filename"
|
|
>localtime</TT
|
|
>. For example:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> $ ln -sf US/Mountain localtime
|
|
$ ln -sf localtime posixrules </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
>This change will take effect immediatelytry <B
|
|
CLASS="command"
|
|
>date</B
|
|
>.
|
|
</P
|
|
><P
|
|
>If the system uses Red Hat-style configuration files, the respective
|
|
time zone info files are <TT
|
|
CLASS="filename"
|
|
>/usr/share/zoneinfo</TT
|
|
> and
|
|
<TT
|
|
CLASS="filename"
|
|
>/etc/localtime</TT
|
|
>.
|
|
</P
|
|
><P
|
|
>The manual pages for <B
|
|
CLASS="command"
|
|
>tzset</B
|
|
> or <B
|
|
CLASS="command"
|
|
>tzselect</B
|
|
> describe setting the
|
|
time zone. Some programs recognize the <TT
|
|
CLASS="literal"
|
|
>TZ</TT
|
|
> environment
|
|
variable, but this is not POSIX-correct.
|
|
</P
|
|
><P
|
|
>You should also make sure that your Linux kernel clock is set to the correct GMT time. Type
|
|
<B
|
|
CLASS="command"
|
|
>date -u</B
|
|
> and check that the correct UTC time is displayed.
|
|
See <A
|
|
HREF="troubleshooting.html#computer-has-wrong-time"
|
|
><I
|
|
>Why Does the Computer Have the Wrong Time?</I
|
|
></A
|
|
>.
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="core-file"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>What Is a <TT
|
|
CLASS="filename"
|
|
>core</TT
|
|
> File?</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>A <TT
|
|
CLASS="literal"
|
|
>core</TT
|
|
>
|
|
file is created when a program terminates unexpectedly, due to a bug, or a
|
|
violation of the operating system's or hardware's protection mechanisms. The
|
|
operating system kills the program and creates a <TT
|
|
CLASS="filename"
|
|
>core</TT
|
|
>
|
|
file that programmers can use to figure out what went wrong. It contains a
|
|
detailed description of the state that the program was in when it died.
|
|
</P
|
|
><P
|
|
>If would like to determine what program a core file came from,
|
|
use the <TT
|
|
CLASS="literal"
|
|
>file</TT
|
|
> command, like this:
|
|
</P
|
|
><P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="screen"
|
|
> $ file core </PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
>
|
|
</P
|
|
><P
|
|
>That will tell you the name of the program
|
|
that produced the core dump. You may want to write the maintainer(s) of the
|
|
program, telling them that their program <EM
|
|
>dumped core.</EM
|
|
>
|
|
</P
|
|
><P
|
|
>[Eric Hanchrow]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="enable-core-dumps"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Enable or Disable Core Dumps</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>By using the <B
|
|
CLASS="command"
|
|
>ulimit</B
|
|
> command in
|
|
<B
|
|
CLASS="command"
|
|
>bash</B
|
|
>, the <B
|
|
CLASS="command"
|
|
>limit</B
|
|
> command in
|
|
<B
|
|
CLASS="command"
|
|
>tcsh</B
|
|
>, or the <B
|
|
CLASS="command"
|
|
>rlimit</B
|
|
> command in
|
|
<B
|
|
CLASS="command"
|
|
>ksh</B
|
|
>. See the appropriate manual page for details.
|
|
</P
|
|
><P
|
|
>This setting affects all programs run from the shell (directly or
|
|
indirectly), not the whole system.
|
|
</P
|
|
><P
|
|
>If you wish to enable or disable core dumping for all processes by default,
|
|
you can change the default setting in <TT
|
|
CLASS="filename"
|
|
>linux/sched.h</TT
|
|
>. Refer to definition of
|
|
<TT
|
|
CLASS="literal"
|
|
>INIT_TASK</TT
|
|
>, and look also in
|
|
<TT
|
|
CLASS="filename"
|
|
>linux/resource.h</TT
|
|
>.
|
|
</P
|
|
><P
|
|
>PAM support optimizes
|
|
the system's environment, including the amount of memory a user is allowed.
|
|
In some distributions this parameter is configurable in the
|
|
<TT
|
|
CLASS="literal"
|
|
>/etc/security/limits.conf</TT
|
|
> file. For more information,
|
|
refer to the <I
|
|
CLASS="citetitle"
|
|
>Linux Administrator's Security Guide</I
|
|
>.
|
|
See <A
|
|
HREF="online-resources.html#howtos-and-other-documentation"
|
|
><I
|
|
>Where Is the Documentation?</I
|
|
></A
|
|
>.
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="remap-keyboard"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Remap a Keyboard to UK, French, Etc.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>For recent kernels, get <TT
|
|
CLASS="filename"
|
|
>/pub/Linux/system/Keyboards/kbd-0.90.tar.gz</TT
|
|
> from
|
|
<A
|
|
HREF="ftp://metalab.unc.edu/"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>ftp://metalab.unc.edu/</I
|
|
></A
|
|
>.
|
|
Make sure you get the appropriate version; you have to use the right keyboard
|
|
mapping package for your kernel version.
|
|
</P
|
|
><P
|
|
>For older kernels you have to edit the top-level kernel
|
|
<TT
|
|
CLASS="filename"
|
|
>Makefile</TT
|
|
>, in <TT
|
|
CLASS="filename"
|
|
>/usr/src/linux/</TT
|
|
>.
|
|
</P
|
|
><P
|
|
>You may find more helpful information in <I
|
|
CLASS="citetitle"
|
|
>The Linux Keyboard and
|
|
Console HOWTO</I
|
|
>, by Andries Brouwer, at
|
|
<A
|
|
HREF="ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/"
|
|
TARGET="_top"
|
|
><I
|
|
CLASS="citetitle"
|
|
>ftp://metalab.unc.edu/pub/Linux/docs/HOWTO/</I
|
|
></A
|
|
>.
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="num-lock-default-on"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Get NUM LOCK to Default to On</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>Use the <B
|
|
CLASS="command"
|
|
>setleds</B
|
|
> program, for
|
|
example (in <TT
|
|
CLASS="filename"
|
|
>/etc/rc.local</TT
|
|
> or one of the
|
|
<TT
|
|
CLASS="filename"
|
|
>/etc/rc.d/*</TT
|
|
> files):
|
|
</P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="programlisting"
|
|
> for t in 1 2 3 4 5 6 7 8
|
|
do
|
|
setleds +num < /dev/tty$t > /dev/null
|
|
done
|
|
</PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
><B
|
|
CLASS="command"
|
|
>setleds</B
|
|
> is part of the
|
|
kbd package ("How do I remap my keyboard to UK, French, etc.? ").
|
|
</P
|
|
><P
|
|
>Alternatively, patch your kernel. You need to arrange for
|
|
<TT
|
|
CLASS="literal"
|
|
>KBD_DEFLEDS</TT
|
|
> to be defined to
|
|
(<TT
|
|
CLASS="literal"
|
|
>1 << VC_NUMLOCK</TT
|
|
>) when compiling
|
|
<TT
|
|
CLASS="filename"
|
|
>drivers/char/keyboard.c</TT
|
|
>.
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="set-terminal-colors"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Set (Or Reset) Initial Terminal Colors</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>The following shell script should
|
|
work for VGA consoles:
|
|
</P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="programlisting"
|
|
> for n in 1 2 4 5 6 7 8;
|
|
do
|
|
setterm -fore yellow -bold on -back blue -store > /dev/tty$n
|
|
done
|
|
</PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>Substitute your favorite colors, and use
|
|
<TT
|
|
CLASS="filename"
|
|
>/dev/ttyS$n</TT
|
|
> for serial terminals.
|
|
</P
|
|
><P
|
|
>To make sure they are reset when people log out (if they've been changed):
|
|
</P
|
|
><P
|
|
>Replace the references to <TT
|
|
CLASS="literal"
|
|
>getty</TT
|
|
> (or
|
|
<TT
|
|
CLASS="literal"
|
|
>mingetty</TT
|
|
> or <TT
|
|
CLASS="literal"
|
|
>uugetty</TT
|
|
> or whatever) in
|
|
<TT
|
|
CLASS="filename"
|
|
>/etc/inittab</TT
|
|
> with references to
|
|
<TT
|
|
CLASS="literal"
|
|
>/sbin/mygetty</TT
|
|
>.
|
|
</P
|
|
><TABLE
|
|
BORDER="0"
|
|
BGCOLOR="#E0E0E0"
|
|
WIDTH="100%"
|
|
><TR
|
|
><TD
|
|
><FONT
|
|
COLOR="#000000"
|
|
><PRE
|
|
CLASS="programlisting"
|
|
> #!/bin/sh setterm -fore yellow -bold on -back blue -store > $1
|
|
exec /sbin/mingetty $@
|
|
</PRE
|
|
></FONT
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><P
|
|
>[Jim Dennis]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="qandaentry"
|
|
><DIV
|
|
CLASS="question"
|
|
><P
|
|
><A
|
|
NAME="more-than-128mb-of-swap"
|
|
></A
|
|
><B
|
|
>Q: </B
|
|
>How To Have More Than 128Mb of Swap</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="answer"
|
|
><P
|
|
><B
|
|
>A: </B
|
|
>Use several swap partitions or swap files.
|
|
Linux kernels before version 2.2 supported up to 16 swap areas, each of up to
|
|
128Mb. Recent versions do not have this limitation.
|
|
</P
|
|
><P
|
|
>Very old kernels only supported swap partition sizes up to 16Mb.
|
|
</P
|
|
><P
|
|
>Linux on machines with 8KB paging, like Alpha and Sparc64, support a swap partition
|
|
up to 512MB. The 128MB limitation comes from
|
|
<TT
|
|
CLASS="literal"
|
|
>PAGE_SIZE*BITSPERBYTE</TT
|
|
> on machines with 4KB paging, but is
|
|
512KB on machines with 8KB paging. The limit is due to the use of a single
|
|
page allocation map.
|
|
</P
|
|
><P
|
|
>The file <TT
|
|
CLASS="filename"
|
|
>mm/swapfile.c</TT
|
|
> has all of the gory details.
|
|
</P
|
|
><P
|
|
>[Peter Moulder, Gordon Weast]
|
|
</P
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="NAVFOOTER"
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"><TABLE
|
|
SUMMARY="Footer navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="common-problems.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="index.html"
|
|
ACCESSKEY="H"
|
|
>Home</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="x-windows.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
>Solutions to Common Problems</TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
> </TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
>The X Window System</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></BODY
|
|
></HTML
|
|
> |