Perl Howto.

Multivalued variables. array
Functions. format

Miscellaneous info.

Nearly all Perl programs I write contain the following three lines; pretty much the only exception being the taint checks, which I omit when being stupidly lazy or when there is no possibility of tainted data.
#!/usr/bin/perl -Tw         # force taint checks, and print warnings
use strict;                 # install all three strictures
$|++;                       # force auto flush of output buffer