i="y"while [ $i = "y" ]
do
echo "1. TO DISPLAY ALL USERS NAMES."
echo "2. USERS NAME OF PARTICULAR GROUP."
echo "3. NAME OF USERS WHO ARE CURRENTLY WORKING ON THE    SYSTEM."
echo "4. EXIT"
echo "ENTER A CHOICE:"
read choice
case $choice in
        1)echo "ALL USERS NAMES ARE:"
          cut -d ":" -f 1 /etc/passwd | more
          read choice;;
        2)echo "ENTER A PARTICULAR GROUP NAME:"
          read g1
         grep "$g1" /etc/passwd | cut -d ":"  -f 1
                read choice;;

        3)who | more
         read choice;;
        4) exit;;
esac
echo "Do u want to continue ? "
read i
if [ $i != "y" ]
then
exit
fi
done












OUTPUT
***********
[04mca58@LINTEL 04mca58]$ sh samegroup.sh
1. to display all users names.
2. users name of particular group.
3. name of users who are currently working on the system.
4. exit
enter a choice:
1                     
all users names are:
root
bin
adm
mca01
mca58

do you want to continue ?
y
1. to display all users names.
2. users name of particular group.
3. name of users who are currently working on the system.
4. exit
enter a choice:
2
enter a particular group name:    
adm
adm         
do you want to continue ?
y
1. to display all users names.
2. users name of particular group.
3. name of users who are currently working on the system.
4. exit
enter a choice:
3          
root     :0       des 12 08:04
mca01    pts/9    des 12 09:10
mca58    pts/10   des 12 09:16
do you want to continue ?
y
1. to display all users names.
2. users name of particular group.
3. name of users who are currently working on the system.
4. exit
enter a choice:
4