How do I extract URLs?

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

This version does not adjust relative URLs, understand alternate bases, deal with HTML comments, deal with HREF and NAME attributes in the same tag, or accept URLs themselves as arguments. It also runs about 100x faster than a more ``complete'' solution using the LWP suite of modules, such as the http://www.perl.com/CPAN/authors/Tom_Christiansen/scripts/xurl.gz program.