$ perl -v | head -2 | tail -1
This is perl 5, version 18, subversion 0 (v5.18.0) built for darwin-thread-multi-2level
$ perl -e 'use 5.020; no 5.024'
Perl v5.20.0 required--this is only v5.18.0, stopped at -e line 1.
BEGIN failed--compilation aborted at -e line 1.
$