Bash-Beginners-Guide

Bash Guide for Beginners
11.2.2. Setting the path
This section might be found in your /etc/profile file. The function pathmunge is defined and then used
to set the path for the root and other users:
pathmunge () {
if ! echo $PATH | /bin/egrep -q "(^|:)$1($|:)" ; then
if [ "$2" = "after" ] ; then
PATH=$PATH:$1
else
PATH=$1:$PATH
fi
fi
}
# Path manipulation
if [ `id -u` = 0 ]; then
pathmunge /sbin
pathmunge /usr/sbin
pathmunge /usr/local/sbin
fi
pathmunge /usr/X11R6/bin after
unset pathmunge
The function takes its first argument to be a path name. If this path name is not yet in the current path, it is
added. The second argument to the function defines if the path will be added in front or after the current PATH
definition.
Normal users only get /usr/X11R6/bin added to their paths, while root gets a couple of extra directories
containing system commands. After being used, the function is unset so that it is not retained.
11.2.3. Remote backups
The following example is one that I use for making backups of the files for my books. It uses SSH keys for
enabling the remote connection. Two functions are defined, buplinux and bupbash, that each make a .tar
file, which is then compressed and sent to a remote server. After that, the local copy is cleaned up.
On Sunday, only bupbash is executed.
#/bin/bash
LOGFILE="/nethome/tille/log/backupscript.log"
echo "Starting backups for `date`" >> "$LOGFILE"
buplinux()
{
DIR="/nethome/tille/xml/db/linux-basics/"
TAR="Linux.tar"
BZIP="$TAR.bz2"
SERVER="rincewind"
RDIR="/var/www/intra/tille/html/training/"
cd "$DIR"
tar cf "$TAR" src/*.xml src/images/*.png src/images/*.eps
echo "Compressing $TAR..." >> "$LOGFILE"
Chapter 11. Functions 134