As mentioned already: yes, the RPi can run one of several Linux distributions. I've run Arch Linux before; currently a version of Debian is on my RPi. The OS is stored on a SD card, which can also act as storage.
The standard "Raspbian" install comes with Perl, and I've used CPAN to install modules (such as the package I mentioned).
I posted this code because I've just discovered how to use the I/O pins to read or write data to/from the outside world, with Perl, on my Raspberry Pi, and I'm excited!