4. Software Configuration

4.1. bash (1)

Arguably, the most important piece of software after the kernel. To tailor the behaviour of bash, these are the main files to edit:

• /etc/bashrc contains system wide aliases and functions;

• /etc/profile contains system wide environment stuff and startup programs;

• $HOME/.bashrc contains user aliases and functions;

• $HOME/.bash_profile contains user environment stuff and startup programs;

• $HOME/.inputrc contains key bindings and other bits.

Examples of these files are shown below. First, the most important: /etc/profile. It's used to configure a lot of features in your Linux box, as you will see in the following sections. Please look out for reverse quotes!

# /etc/profile # System wide environment and startup programs # Functions and aliases go in /etc/bashrc # This file sets up the following features and programs: # path, prompts, a few environment variables, colour ls, less, # rxvt, Backspace key behaviour, xterm title. # # Users can override these settings and/or add others in their # $HOME/.bash_profile # first: root or normal user? Set PATH and umask accordingly. Note that the # PATH is normally set by login (1), but what if you access the machine # via ssh? if [ $(id -gn) = $(id -un) -a $(id -u) -gt 14 ]; then umask 002 # normal user PATH="/usr/local/bin:/bin:/usr/bin:." else umask 022 # root PATH="/sbin:/bin:/usr/sbin:/usr/bin" fi # Now extend the PATH. PATH="$PATH:/usr/X11R6/bin:$HOME/bin:." # !!! Beware of ./ !!! # notify the user: login or non-login shell. If login, the prompt is # blue; otherwise, magenta. Root's prompt is red. # See the Colour-ls mini HOWTO for an explanation of the escape codes. USER=$(whoami) if [ $LOGNAME = $USER ] ; then COLOUR=44 # blue else COLOUR=45 # magenta fi if [ $USER = 'root' ] ; then COLOUR=41 # red PATH="$PATH:/usr/local/bin" # my choice fi ESC="\033" PROMPT='\h' # hostname STYLE='m' # plain # PROMPT='\u' # username # STYLE=';1m' # bold PS1="\[$ESC[$COLOUR;37$STYLE\]$PROMPT:\[$ESC[37;40$STYLE\]\w\\$ " PS2="> " # Ulimits: no core dumps, max file size 200 Mb. ulimit -c 0 -f 200000 # a few variables USER=$(id -un) LOGNAME=$USER MAIL="/var/spool/mail/$USER" # sendmail, postfix, smail # MAIL="$HOME/Mailbox" # qmail NNTPSERVER=news.myisp.it # put your own here VISUAL=jed EDITOR=jed HOSTNAME=$(/bin/hostname) HISTSIZE=1000 HISTFileSIZE=1000 export PATH PS1 PS2 USER LOGNAME MAIL NNTPSERVER export VISUAL EDITOR HOSTNAME HISTSIZE HISTFileSIZE # enable colour ls eval $(dircolors /etc/DIR_COLORS -b) export LS_OPTIONS='-s -F -T 0 --color=yes' # customize less LESS='-M-Q' LESSEDIT="%E ?lt+%lt. %f" LESSOPEN="| lesspipe.sh %s" LESSCHARDEF=8bcccbcc13b.4b95.33b. # show colours in ls -l | less # LESSCHARSET=latin1 PAGER=less export LESS LESSEDIT LESSOPEN VISUAL LESSCHARDEF PAGER # you might need this to fix the backspace key in rxvt/xterm stty erase ^H # alternative: ^? # set xterm title: full path case $TERM in xterm*|rxvt) PROMPT_COMMAND='echo -ne "\033]0;${USER}@${HOSTNAME}: ${PWD}\007"' ;; esac for i in /etc/profile.d/*.sh ; do if [ -x $i ]; then . $i # beware - variables and aliases might get overridden! fi done # call fortune, if available if [ -x /usr/games/fortune ] ; then echo ; /usr/games/fortune ; echo fi

This is a sample /etc/bashrc:

# /etc/bashrc # System wide functions and aliases # Environment stuff goes in /etc/profile # Insert PS1 definitions here if you experience problems. export CDPATH="$CDPATH:~" # common aliases alias cp='cp -i' alias l=less alias ls="ls $LS_OPTIONS" alias mv='mv -i' alias rm='rm -i' alias rmbk='/bin/rm -f .*~ *~ *aux *bak *log *tmp 2> /dev/null' alias u='cd ..' alias which="type -path" alias x=startx # A few useful functions c () # cd to the new directory and list its contents { cd $1 ; ls } inst() # Install a .tar.gz archive in current directory { if [ $# != 0 ]; then tar zxvf $1; fi } cz() # List the contents of a .zip archive { if [ $# != 0 ]; then unzip -l $*; fi } ctgz() # List the contents of a .tar.gz archive { for file in $* ; do tar ztf ${file} done } tgz() # Create a .tgz archive a la zip. { if [ $# != 0 ]; then name=$1.tar; shift; tar -rvf ${name} $* ; gzip -9 ${name} fi } crpm() # list information on an .rpm file { if [ $# != 0 ]; then rpm -qil $1 | less; fi }

This is a sample .bashrc:

# $HOME/.bashrc # Source global definitions if [ -f /etc/bashrc ]; then . /etc/bashrc fi # this is needed to notify the user that they are in non-login shell if [ "$GET_PS1" = "" ] ; then COLOUR=45; ESC="\033"; STYLE=';1m'; # STYLE='m' USER=$(whoami) export PS1="\[$ESC[$COLOUR;37$STYLE\]$USER:\[$ESC[37;40$STYLE\]\w\\$ " fi # personal aliases alias backup='tar -Mcvf /dev/fd0' alias dial='eznet up myisp' alias f='cd ~/fortran' alias hangup='eznet down' alias lyx='lyx -width 580 -height 450' alias restore='tar -M -xpvf /dev/fd0' # personal functions xj() # Launch xjed and a file in background { xjed $1 & }

This is a sample .bash_profile:

# $HOME/.bash_profile # User specific environment and startup programs # This file contains user-defined settings that override # those in /etc/profile # Get user aliases and functions if [ -f ~/.bashrc ]; then GET_PS1="NO" # don't change the prompt colour . ~/.bashrc fi # set a few `default' directories export CDPATH="$CDPATH:$HOME:$HOME/text:$HOME/text/geology"

This is a sample .inputrc:

# $HOME/.inputrc # key bindings "\e[1~": beginning-of-line "\e[3~": delete-char "\e[4~": end-of-line # (F1 .. F5) are "\e[[A" ... "\e[[E" "\e[[A": "info \C-m" set bell-style visible # please don't beep set meta-flag On # allow 8-bit input (i.e, accented letters) set convert-meta Off # don't strip 8-bit characters set output-meta On # display 8-bit characters correctly set horizontal-scroll-mode On # scroll long command lines set show-all-if-ambiguous On # after TAB is pressed

To make the backspace and delete keys work correctly in xterm and other X11 applications, the following is also needed:

• put this in your .xinitrc:

  usermodmap=$HOME/.Xmodmap xmodmap $usermodmap

• then your .Xmodmap will contain:

  keycode 22 = BackSpace keycode 107 = Delete

  this fixes the console. To fix xterm:

• put this in your .Xdefaults:

  xterm*VT100.Translations: #override <Key>BackSpace: string(0x7F)\n\ <Key>Delete: string(0x1b) string("[3~")\n\ <Key>Home: string(0x1b) string("[1~")\n\ <Key>End: string(0x1b) string("[4~")\n\ Ctrl<Key>Prior: string(0x1b) string("[40~")\n\ Ctrl<Key>Next: string(0x1b) string("[41~") nxterm*VT100.Translations: #override <Key>BackSpace: string(0x7F)\n\ <Key>Delete: string(0x1b) string("[3~")\n\ <Key>Home: string(0x1b) string("[1~")\n\ <Key>End: string(0x1b) string("[4~")\n\ Ctrl<Key>Prior: string(0x1b) string("[40~")\n\ Ctrl<Key>Next: string(0x1b) string("[41~")

rxvt is a wee bit more complicated, as some compile--time options influence its behaviour. See the above /etc/profile.

More info in bash (1) and readline (3) man pages.

Don't expect every application to work correctly! If you run joe in xterm, for instance, some keys won't work; the same holds for some versions of rxvt.

4.2. I18n

(This section doesn't apply to native English speakers.)

A.k.a. ``internationalisation''. Gasp. This long word means ``to adapt Linux to your local conventions: language, format of date, currency etc.''.

Although Red Hat has its own method for setting up i18n (/etc/sysconfig/i18n), you may want to enable your language only in some cases. I, for one, enabled i18n in kdm (via kdmconfig) and xfce, but want to read English messages when I work in console or xterm.

Consider these lines:

LANG=it # choose your language: fr, de, es, ... LANGUAGE=it LC_ALL=it export LANG LANGUAGE LC_ALL

If you insert them in your .xinitrc or .xsession just before the line that starts the window manager, you'll get internationalised messages - including those in xterms started from within the window manager. But if you'd rather get English messages, set the language to ``en'' and put the same lines in .bash_profile.

4.3. ls (1)

ls can display directory listings using colours to highlight different file types. To enable this feature, you just need a couple of lines in /etc/profile as seen above. However, this won't work with old versions of rxvt; use some flavour of xterm instead. It looks like some old rxvts have a bug that prevents them from inheriting the environment correctly in some circumstances.

4.4. less (1)

With this excellent pager you can browse not only plain text files, but also gzip compressed, tar and zip archives, man pages, and what have you. Its configuration involves a few steps:

• to use it with the movement keys, have this plain ASCII file .lesskey in your home directory:

  ^[[A back-line ^[[B forw-line ^[[C right-scroll ^[[D left-scroll ^[OA back-line ^[OB forw-line ^[OC right-scroll ^[OD left-scroll ^[[6~ forw-scroll ^[[5~ back-scroll ^[[1~ goto-line ^[[4~ goto-end ^[[7~ goto-line ^[[8~ goto-end

  then run the command lesskey. (These are escape sequences for vt100-like terminals.) This creates a binary file .less containing the key bindings.

• write the following file as /usr/bin/lesspipe.sh:

  #!/bin/sh # This is a preprocessor for 'less'. It is used when this environment # variable is set: LESSOPEN="|lesspipe.sh %s" lesspipe () { case "$1" in *.tar) tar tf $1 2>/dev/null ;; # View contents of .tar and .tgz files *.tgz|*.tar.gz|*.tar.Z|*.tar.z) tar ztf $1 2>/dev/null ;; *.Z|*.z|*.gz) gzip -dc $1 2>/dev/null ;; # View compressed files correctly *.tar.bz2) bzip2 -dc $1 | tar tf - ;; *.bz2) bzip2 -dc $1 2>/dev/null ;; *.zip) unzip -l $1 2>/dev/null ;; # View archives *.arj) unarj -l $1 2>/dev/null ;; *.rpm) rpm -qpil $1 2>/dev/null ;; *.cpio) cpio --list -F $1 2>/dev/null ;; *.1|*.2|*.3|*.4|*.5|*.6|*.7|*.8|*.9|*.n|*.l|*.man) file $1 | grep roff > /dev/null if [ $? = 0 ]; then groff -Tascii -mandoc $1 fi ;; *) file $1 | grep "te[sx]t" > /dev/null ; if [ $? = 1 ] ; then # it's not some kind of text strings $1 fi ;; esac } # treat link targets, not links themselves file $1 | grep symbolic > /dev/null if [ $? = 0 ]; then TARGET=$(file $1 | awk '{print $NF}') lesspipe $TARGET else lesspipe $1 fi

  then make it executable with chmod 755 lesspipe.sh.

• put the variables that affect less in /etc/profile as seen above.

4.5. Editor

Only the most popular will be covered here.

4.6. pine (1)

Edit the global configuration in /usr/lib/pine.conf, taking care at least of the following fields: user-domain, smtp-server, and nntp-server. Note that inbox-path depends on your MTA: if you use sendmail or postfix, that'll be var/spool/mail/$USER; with Qmail, /home/$USER/Mailbox (but root will use /var/qmail/alias/Mailbox.

4.7. minicom (1)

Users can't use minicom unless a global configuration has been made by root. Remember to make it.

4.8. efax (1)

This package is probably the most convenient for simple sending/receiving of faxes. You'll have to tailor the script /usr/bin/fax or (mandrake) /etc/fax.config; easy job, but a couple of quirks caused me quite a headache:

• to find out whether your modem is class 1, 2, or 2.0, use minicom or similar program to issue the command at+fclass=?. The reply may be like 0,1,2; 1 and 2 are the classes supported by your modem;

• DIALPREFIX: chances are that simply putting `T' or `P' won't work in some countries-in Italy, at least. Put `ATDT' or `ATDP' instead;

• INIT and RESET: these strings contain the initialisers `-i' and `-k', needed by efax. If you want to add an AT command, add it to the appropriate string leaving out `AT' and preceding the rest with either `-i' or `-k'. Example: to add the `ATX3' command to INIT, you'll append `-iX3'.

That done, there are a few permissions to fix to enable non-root users to send and receive faxes. The directories /var/lock and /var/spool/fax must be writable. To do so, create the group faxusers, add users to it, then type:

~# chown root.faxusers /var/lock ~# mkdir /var/spool/fax # if it doesn't exist yet ~# chown root.faxusers /var/spool/fax; chmod g+w /var/spool/fax

As a normal user, you'll issue newgrp faxusers before sendig a fax.

4.9. Ghostscript

This essential tool suffers from a small snag. Owing to to the well-known export regulations in the USA, the utility pdf2ps doesn't work with encrypted .pdf files. Never mind: point your browser to http://www.ozemail.com.au/~geoffk/pdfencrypt, download the file pdf_sec.ps and replace the file with the same name that comes with the Ghostscript distribution.

4.10. TeX and Friends

The ``root'' of a TeX system is the directory $TEXMF, which is /usr/share/texmf in teTeX; other distributions may differ (search for ``texmf'' on your system). You normally add stuff or fiddle with files therein.

4.11. Docbook

LaTeX is the best choice for typesetting, Docbook for multiformat documents (This HOWTO is written in Docbook.) Once you get all of the tools in place, you'll want to use simple scripts to avoid the complex command line. If these are not provided with the distribution, use the following db2pdf as template:

#!/bin/sh

if [ $# = 0 ]; then
  echo "Usage: db2pdf <file.sgml> [file2.sgml ...]"
  exit 1
fi

# Standard Mandrake location:
DSSSL=/usr/share/sgml/docbook/dsssl-stylesheets-1.57/print/docbook.dsl
# Standard RedHat location:
# /usr/lib/sgml/stylesheets/nwalsh-modular/print/docbook.dsl

if [ ! -f $DSSSL ]; then
  DSSSL=$(find /usr/ -name "docbook.dsl" | grep print)
fi

for FILE in $*
do
  NAME=$(echo $FILE | awk -F'.' '{print $1}')
  echo "Processing $FILE..."
  jade -t tex -d $DSSSL $NAME.sgml
  pdfjadetex $NAME.tex
done

# End of db2pdf

If you find that your PostScript od .PDF looks very bad, the file to hack is dbparams.dsl. In my Mandrake system, it's located in /usr/share/sgml/docbook/dsssl-stylesheets-1.57/print/.

4.12. Avoid PPProblems!

I'll take it for granted that your kernel has PPP + TCP/IP support compiled in, that loopback is enabled, and that you already have the pppd package correctly installed and, if you will, set uid root. Obviously, your ISP must support PPP.

There are now two ways to get PPP to work: a) manual configuration, and b) a configuration program that automagically sees to it. Whichever option you choose, have the following information on hand:

• your ISP's telephone number;

• your ISP's name, mail and news server address;

• your ISP's domain;

• your username and password.

Manual configuration is a drudgery. It's about editing files and writing scripts; not too much work, but it's easy to make mistakes and newcomers are often intimidated. The PPP HOWTO is there for you. Alternatively, there are tools that ask for the information above and do all the work.

Gnome and KDE include, respectively, gnome-ppp and kppp which are easy enough to set up. Alternatively, I suggest that you have a look at a couple of tty--based tools, wvdial and eznet. You feed them your ISP's phone number, your username, your password, and you're in business. Their home pages are at http://www.worldvisions.ca/wvdial and http://www.hwaci.com/sw/eznet. Both are great, but I prefer the latter.

4.13. POP Client

To retrieve your mail from a POP3 server, you need a POP client. Most such clients require that you run an MTA like sendmail, qmail or postfix; a bit of an overkill on low-spec machines. However, there are clients that work without an MTA. The first kind is well represented by fetchmail; the second by fetchpop or frenchie. Sites: ftp://metalab.unc.edu/pub/Linux/system/mail/pop, http://www.lowcountry.com/~jscottb/tcltk.shtml.

To configure these clients:

• fetchpop: the first time you run it, you'll be prompted for some information. Answer the questions and you're set. fetchpop must be used with the -r switch if your ISP's POP3 server doesn't implement the command LAST properly.

• frenchie: as above, edit  /.frenchie/frenchierc;

• fetchmail: adapt this sample .fetchmailrc:

  # $HOME/.fetchmailrc poll mbox.myisp.com with protocol pop3; user john there with password _Loo%ny is john here

  One user reported that adding ``smtphost localhost'' to the second line improved performance dramatically. You must set the permissions to this file with the command chmod 600 .fetchmailrc, otherwise fetchmail will rightly refuse to start. This example is very basic; there are endless possibilities of configuration. Check out at http://www.ccil.org/~esr/fetchmail.

4.14. Basic Mail Filtering

You will want to protect yourself from spam or huge mail messages. There are two cases: 1) permanent connection to the net, 2) a POP link. In the first case, you can write a .procmailrc file, while in the second there are tools for checking the mail prior to fetching it.

A very simple .procmailrc that defines a few rules:

# $HOME/.procmailrc MAILDIR=$HOME/mail # make sure it exists # Store messages directed to the "foo" mailing list to $HOME/mail/foo :0 * ^To:.*foo foo # Discard messages that are not explicitly sent to me or to one of the # mailling lists I subscribed to. :0 * !^TO(guido|jed|lugvr|ldp|nobody) /dev/null # ditto, for messages larger than 50k. :0 * > 50000 /dev/null

man procmailex for further examples.

POP users will want to use poppy, a useful Perl script for checking the mail before fetching it. Get it from ftp://metalab.unc.edu/system/mail/pop.

4.15. X Window System (XFree86)

4.16. Users' Configurations

When you're done editing the dot files, copy them to /etc/skel as seen in Section Section 4.

4.17. Making .rpms

rpm is such a wonderful method of keeping packages under control that I'm reluctant to install .tar.gz archives but in very few special cases (e.g., security). Whenever you install a tarball, consider turning it into an .rpm archive, then reinstall it; consult the RPM HOWTO. Also, if you use recent gcc versions, it may be advisable to put this in your /etc/rpmrc:

optflags: i386 -O2 -mpentiumpro

4.18. Upgrading

If you upgrade your machine, do your backup as usual and remember to save a few additional files. Some could be /etc/X11/XF86Config, /usr/bin/fax, all the stuff in /usr/local, the kernel configuration, the whole /etc, and all the mail in /var/spool/mail.

Then it's time to upgrade (in rare cases, downgrade!) applications that your distribution ship with, and to add additional packages. Keep a list of these ones.