idcheck

Unix Shell编程权威指南的配套源代码,书是好书,不过习题没有答案,要自己做了

#!/bin/bash
# Scriptname: idcheck
# purpose:check user id to see if user is root.
# Only root has a uid of 0.
# Format for id output:uid=9496(ellie) gid=40 groups=40
# root's uid=0 

id=`id | gawk -F'[=(]'  '{print $2}'`     # get user id
echo your user id is: $id
if  (( id == 0 ))    # [ $id -eq 0 ] (See cd file: idcheck2)
then 
	echo "you are superuser."
else
	echo "you are not superuser."
fi