perl common regexps

Note: these tend to be "good enough", not necessarily "pedantically correct".

IPv4 address (decimal)

    m#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#

MAC address

    m#\d{2}:\d{2}:\d{2}:\d{2}:\d{2}:\d{2}#
    m#\d{4}\.\d{4}\.\d{4}#

URL and description (overly simple)

    m#(.*)#i    # returns URL in $1, text in $2

extract URLs (via qxurl by tchrist from perlfaq9)

    # returns URL in $2, text in $3
    m#<\s*a\s*href\s*=\s*(["'])(.*?)\1\s*>(.*)#gsix

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