Shell Programming and Scripting

#!/bin/bash
if [ $# -eq 0 ]
then
echo "$(basename $0) <filename>"
fi

case $1 in
        userlist)
        if [ -f /home/ar/users.txt ]
        then
        for user in `cat /home/ar/users.txt|awk -F: '{print $1}'`
        do
        useradd -s /bin/false $user
        done
        echo "file is tehre"
        else
        echo "Input file is no there"
        fi
        ;;
esac


#cat users.txt
proxysync:x:1008:1008:Proxy Sync User:/home/proxysync:/bin/bash
gluster:x:992:988:GlusterFS daemons:/var/run/gluster:/sbin/nologin

#!/bin/bash
if [ $# -eq 0 ]
then
   echo "$(basename $0) <filename>"
   exit 1
fi

case $1 in
    userlist)
        if [ -f /home/ar/users.txt ]
        then
           for user in `cat /home/ar/users.txt|awk -F: '{print $1}'`
           do
              useradd -s /bin/false $user
           done
           echo "file is tehre"
        else
           echo "Input file is no there"; exit 2
        fi
    ;;
    *) echo "Input File Not Found" ; exit 3;;
esac

$ ./myuseradd
myuseradd <filename>
$ echo $?
1

$ ./myuseradd userlist
Input file is no there
$ echo $?
2

$ ./myuseradd rubbish
Input File Not Found
$ echo $?
3