Hello, Good day!!!

1. Sorry i have no idea :(

2. Hmmmm...well.., there are a lot of decent modules found in CPAN. I think it should be better if you're going to read perlthrtut and perlothrtut first ^_^

3. As what have JadeNB said, you can use /g flag to get all strings that have matched w/ the pattern.

Example:

#!/usr/local/bin/perl -w

use strict;

my $str = "12345-112316 string string 11111-222311\n\n 71231-121111";

# assuming '-' is the delimiter
my @pnumbers = $str=~/(\d+-\d+)/g;

# print
print "$_\n" foreach(@pnumbers);
[download]

You might want to read perlretut also for better understading of regular expressions (regex)...

Cheers!!!