Regular Expression Pocket Reference, 2nd Edition

Examples

Example 1-1. Simple match

# Find Spider-Man, Spiderman, SPIDER-MAN, etc.
my $dailybugle = "Spider-Man Menaces City!";
if ($dailybugle =~ m/spider[- ]?man/i) { do_something(  ); }

Example 1-2. Match, capture group, and qr

# Match dates formatted like MM/DD/YYYY, MM-DD-YY,...
my $date  = "12/30/1969";
my $regex = qr!^(\d\d)[-/](\d\d)[-/](\d\d(?:\d\d)?)$!;
if ($date =~ $regex) {
  print "Day=  ", $1,
        " Month=", $2,
        " Year= ", $3;
}

Example 1-3. Simple substitution

# Convert <br> to <br /> for XHTML compliance
my $text = "Hello World! <br>";
$text =~ s#<br>#<br />#ig;

Example 1-4. Harder substitution

# urlify - turn URLs into HTML links
$text = "Check the web site, http://www.oreilly.com/catalog/
regexppr.";
$text =~
     s{
      \b                         # start at word boundary
      (                          # capture to $1
       (https?|telnet|gopher|file|wais|ftp) :
                                 # resource and colon
       [\w/#~:.?+=&%@!\-] +?     # one or more valid
                                 # characters
                                 # but take as little as
                                 # possible
      )
      (?=                        # lookahead
           [.:?\-] *             #  for possible punctuation
        (?: [^\w/#~:.?+=&%@!\-]  #  invalid character
          | $ )                  #  or end of string
      )
     }{<a href="$1">$1</a>}igox;