Perl is installed by default.
You can download the code from www.perl.com and build the newest version from source if you want to, although a stable and quality release of Perl is already installed by default in Ubuntu and most (all?) Linux and UNIX-like distributions, including Mac OS X. Updated versions might appear in the Ubuntu repositories, but they’re generally only security fixes that can be installed by updating your system. See Chapter 9, “Managing Software,” to see how to quickly get a list of available updates for Ubuntu.
You can determine what version of Perl you installed by typing
perl -v at a shell prompt. If you are installing the latest Ubuntu distribution, you should have the latest version of Perl that was available ...