Shell Script for comparing files

read f1
echo -n "Enter File 2 name :- "
read f2
echo "1.cmd"
echo "2.diff"
echo "3.sdiff"
echo -n "Enter your choice:- "
read ch
case $ch in
1)
echo "===========Comparision using cmp command=========="
cmp $f1 $f2
;;
2)
echo "===========Comparision using diff command=========="
diff $f1 $f2
;;
3)
echo "===========Comparision using sdiff command=========="
exec sdiff $f1 $f2
;;
*)
echo "Invalid Option"
esac