OSA:[GRP A-5] PROCESS INFO

while (true)
do
echo "enter your choice
    1.current shell
    2. process information
    3.global priority
    4.change priority of process
    5. exit";
read a;
case $a in
1)echo"current shell";
read b;
ps b;
;;
2)echo" process information";
read c;
ps -f $c;
;;
3)echo"global priority";
read d;
ps -ao tty nice $d;
;;
4)echo"change priority of process";
read e;
ps -f $e;
echo"which want to change priority of process";
read f;
echo"enter parent id";
read g;
renice $f$g;
;;
5)exit 0
;;
esac;
done