That shouldn't even compile/run:

Global symbol "$cmd1" requires explicit package name at try4.pl line 3.
Global symbol "$cmd1" requires explicit package name at try4.pl line 4.
Global symbol "$cmd" requires explicit package name at try4.pl line 5.
Global symbol "$cmd1" requires explicit package name at try4.pl line 6.

Apart from not using "my" to declare your variables, notice that you reference $cmd, which isn't actuallly declared/assigned to anywhere.