in reply to Perl regular expression question

For further information, give the command 
perldoc perlre

[download]
perlre is the manual page for regular expressions in perl.
perldoc accesses this manual page.

perlre probably contains much more than you want at this stage, but at least you would know the kind of thing that's available for when you need it in the future.

In Section Seekers of Perl Wisdom