from: http://www.cyberciti.biz/faq/howto-installing-perl-on-freebsd/
Q. I need Perl programming language to run scripts. How do I install perl on FreeBSD operating system? 
A. Practical Extraction and Report Language or Perl can be installed using FreeBSD ports or binary package system. Perl is a language optimized for scanning arbitrary text files, extracting information from those text files, and printing reports based on that information. It's also a good language for many system management tasks. The language is intended to be practical (easy to use, efficient, complete) rather than beautiful (tiny, elegant, minimal).
Install perl using FreeBSD ports
Perl5 port is located at /usr/ports/lang/perl5.8. Type the command as follows to install Perl5:#
cd /usr/ports/lang/perl5.8
# make;make install;make clean
Now perl will be installed and binary path to perl is /usr/local/bin/perl.
Install perl using FreeBSD pkg_add command
Just type the following command:#
pkg_add -v -r perl