Linux: pathmunge Command in Shell Script

Q. I see pathmunge used in few scripts under Red Hat Enterprise Linux. Can you explain the use of pathmunge under RHEL / CentOS / Fedora Linux?

A. Red Hat, CentOS, and Fedora Linux has a pathmunge function defined in /etc/profile file. It will add the directories one by one to the default PATH for the root user.

pathmunge() function is defined in /etc/profile

pathmunge () {
        if ! echo $PATH | /bin/egrep -q "(^|:)$1($|:)" ; then
           if [ "$2" = "after" ] ; then
              PATH=$PATH:$1
           else
              PATH=$1:$PATH
           fi
        fi
}

Path manipulation done using pathmunge:

# Path manipulation
if [ "$EUID" = "0" ]; then
        pathmunge /sbin
        pathmunge /usr/sbin
        pathmunge /usr/local/sbin
fi

As long as you are using Red Hat or CentOS / Fedora Linux, you can use pathmunge. It is best to avoid this function if you need run a shell script on diffrent distributions. I recommend using export bash command for modifying PATH variable.