Super Search turned up these threads:

• help needede in backticks(``) and system function
• How do I get both the return value and text? backticks vs. system()
• How to run a shell script from a Perl program?
• system() vs `backtick`
• The difference between [system] and `backticks` and [qx//] (on win32)

Also see the section on `STRING` in perlop and system.

HTH