Are you root?

/*

*By Neil Chiao ( neilchiao at gmail.com )

*From ( neilengineer.cublog.cn )

*/

 

 

 

#!/bin/bash

 

#The first way
case `id -u` in
0)
       ;;
*)
       echo "gnome-xgl-switch must be run as root" 1>&2
       exit 1
       ;;
esac

#Another way
 if [ "$(id -un)" != "root" ]; then
              echo "This script has to be run by root, quit now"
              exit
 fi