How do I extract URLs?

You can easily extract all sorts of URLs from HTML with HTML::SimpleLinkExtor which handles anchors, images, objects, frames, and many other tags that can contain a URL. If you need anything more complex, you can create your own subclass of HTML::LinkExtor or HTML::Parser. You might even use HTML::SimpleLinkExtor as an example for something specifically suited to your needs.

Less complete solutions involving regular expressions can save you a lot of processing time if you know that the input is simple. One solution from Tom Christiansen runs 100 times faster than most module based approaches but only extracts URLs from anchors where the first attribute is HREF and there are no other attributes.

        #!/usr/bin/perl -n00
        # qxurl - tchrist@perl.com
        print "$2\n" while m{
            < \s*
              A \s+ HREF \s* = \s* (["']) (.*?) \1
            \s* >
        }gsix;