Write Coding to validate the .pl Files

[kanish]

Dear Monks,

I have a .pl file which was done by perl trainers.

I need to write the code to validate the .pl file which was done by perl trainers.

The following are I have to write code to validate them.

1. Find the unncessary grouping. i.e.

$a=~s#(foo)(bar)#$1#;

Here first group only given in replace, but second group not in replace. So It'll eat memory unnecessarily.

2. If variable declared, but not in use anywhere. It'll show.

3. If there is a subroutine, but it'll not call anywhere, It'll show.

...

...

I need to validate these things in my coding. Please give if there is any short way or any modules.

Thanks in Advance.

Kanishk