#!/bin/sh

CMT="RPM User Account" 

chkrpm() {
    echo "ADD=1" > /tmp/chk$$
    awk ' BEGIN { FS=":" } { print $1 } ' $1 | while read f
    do
        [ "$f" = "rpm" ] && echo "ADD=" > /tmp/chk$$
    done
}

addgrprpm() {
    groupadd rpm
}

addusrrpm() {
    useradd -g rpm -d /var/lib/rpm -s /bin/false -c "$CMT" rpm
}

chkrpm /etc/group
. /tmp/chk$$
[ "$ADD" ] && addgrprpm
chkrpm /etc/passwd
. /tmp/chk$$
[ "$ADD" ] && {
    addusrrpm
}
rm -f /tmp/chk$$