Write a shell script to accept the name of the user and check out if the same has logged in or not

echo Enter user name:

read user

f=1

for i in `who|tr -s " "|cut -d " " -f 1`

do

if [ $i = $user ]

then

echo The user is login now

f=0

break

fi

done

if [ $f != 0 ]

then

echo The user is logged off

fi