sort -n '-t:' +2 -3 -o /etc/passwd /etc/passwd
uid=`tail -1 /etc/passwd | sed -n "s/[^:]*:[^:]*:\\([^:]*\\).*/\\1/p"`

while expr $# "!=" "0" > /dev/null
do
	if grep "$1:.*" /etc/passwd
	then
		echo "user name '$1' already taken"
		shift
	else
		uid=`expr $uid "+" "1"`
		echo "$1::$uid:5::/u/$1:/bin/sh" >> /etc/passwd
		mkdir /u/$1
		chown $1 /u/$1
		shift
	fi
done
