Corollary: be wary using the OS' perl because that then puts your application (whatever your particular value of "application" might be) at the mercy of the OS' upgrade schedule. If you're doing anything significant use perlbrew or the like to build your own, separate perl; then use that install to install CPAN modules and run your code. You'll be glad for the decoupling when the system upgrade pulls in something that would break your application code.