See perldoc for system and exec and backticks (`) ...
or use a search tool... Google, Super Search or your fav...
and don't forget to check out Tutorials and Q&A sections here.

This is really to sort of question for which you need to start finding answers yourself (by use of tools like those cited and the rich resources here). Once you've done that, you'll find the Monks generous with explanations when you hit a stumbling block whose solution lies beyond the basics.