My Technical Memories - Memory 3

Ah! What is it? I could see a  lot of symbols. I had to ponder about it  a bit… Na.. I am joking. How can I ever forget Unix Shell Scripts? I have a long lasting relationship with it. It is really interesting to read my thoughts after a long… long… time. Here comes a small and simple snippet of thoughts….

Unix Shell Script to check every minute whether a user is logged in or not?

# usage is : scriptname.sh username

if [ $# -lt 1 ]; then

   echo improper usage

   echo Correct usage is : $0 username

   exit 1

fi

logname=$1

time=0

while true

do

    who | grep `$logname`  > /dev/null

    if [ $? –eq 0 ] ; then

       echo $logname has logged in

       if [ $time – ne 0 ]; then

         echo $logname is $time minutes late

       fi

      exit 0

    else

     time=`expre $time + 1`

     sleep 60

    fi

done

Unix and its look alike or derivatives are really amazing, may it be linux, solaris, venix, xenix, HP-unix, SCO- Unix. I hope I recollected my memory accurately. Why don’t you just execute and check… Lot more on its way… see you again later….