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NAME

perlfaq6 - Regular Expressions ($Revision: 1.12 $, $Date: 2002/06/01 22:31:09 $)

DESCRIPTION

This section is surprisingly small because the rest of the FAQ is littered with answers involving regular expressions. For example, decoding a URL and checking whether something is a number are handled with regular expressions, but those answers are found elsewhere in this document (in

• How can I hope to use regular expressions without creating illegible and unmaintainable code?
• Comments Outside the Regex
• Comments Inside the Regex
• Different Delimiters
• I'm having trouble matching over more than one line. What's wrong?
• How can I pull out lines between two patterns that are themselves on different lines?
• I put a regular expression into $/ but it didn't work. What's wrong?
• How do I substitute case insensitively on the LHS while preserving case on the RHS?
• How can I make \w match national character sets?
• How can I match a locale-smart version of /[a-zA-Z]/?
• How can I quote a variable to use in a regex?
• What is /o really for?
• How do I use a regular expression to strip C style comments from a file?
• Can I use Perl regular expressions to match balanced text?
• What does it mean that regexes are greedy? How can I get around it?
• How do I process each word on each line?
• How can I print out a word-frequency or line-frequency summary?
• How can I do approximate matching?
• How do I efficiently match many regular expressions at once?
• Why don't word-boundary searches with \b work for me?
• Why does using $&, $`, or $' slow my program down?
• What good is \G in a regular expression?
• Are Perl regexes DFAs or NFAs? Are they POSIX compliant?
• What's wrong with using grep or map in a void context?
• How can I match strings with multibyte characters?
• How do I match a pattern that is supplied by the user?

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