Perl Programming/Keywords/pop

The pop keyword
pop pops and returns the last value of the array by shortening it by this element. Returns undef, if the array is empty. If ARRAY is omitted, it pops @ARGV in the main program, and @_ array in subroutines, just like shift.

From Perl 5.14.0 onwards, a scalar EXPRESSION can be passed that should hold a reference to an unblessed array. The argument is dereferenced automatically. This is a highly experimental aspect of <tt>pop</tt> and may change in future Perl versions.