Shell Script 'action' Command

'action' is defined inside a library called functions. You have to source your script first with this library in order to use it. This library is a distro distribution dependent and none of these distro libraries are compatible with the others. In Ubuntu is /lib/lsb/init-functions, SuSE has /etc/rc.status and in Centos is /etc/rc.d/init.d/functions. Some distributions don't use it at all.

Example of 'action':

# Source function library.
. /etc/rc.d/init.d/functions

# Now you can use action:
action $"Perform an action:" /bin/true

In Centos 7, 'action' definition inside /etc/rc.d/init.d/functions is as the following:

# Run some action. Log its output.
action() {
    local STRING rc

    STRING=$1
    echo -n "$STRING "
    shift
    "$@" && success $"$STRING" || failure $"$STRING"
    rc=$?
    echo
    return $rc
}