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gawk: Regexp

 
 3 Regular Expressions
 *********************
 
 A "regular expression", or "regexp", is a way of describing a set of
 strings.  Because regular expressions are such a fundamental part of
 'awk' programming, their format and use deserve a separate major node.
 
    A regular expression enclosed in slashes ('/') is an 'awk' pattern
 that matches every input record whose text belongs to that set.  The
 simplest regular expression is a sequence of letters, numbers, or both.
 Such a regexp matches any string that contains that sequence.  Thus, the
 regexp 'foo' matches any string containing 'foo'.  Thus, the pattern
 '/foo/' matches any input record containing the three adjacent
 characters 'foo' _anywhere_ in the record.  Other kinds of regexps let
 you specify more complicated classes of strings.
 

Menu

 
· Regexp Usage                How to Use Regular Expressions.
· Escape Sequences            How to write nonprinting characters.
· Regexp Operators            Regular Expression Operators.
· Bracket Expressions         What can go between '[...]'.
· Leftmost Longest            How much text matches.
· Computed Regexps            Using Dynamic Regexps.
· GNU Regexp Operators        Operators specific to GNU software.
· Case-sensitivity            How to do case-insensitive matching.
· Regexp Summary              Regular expressions summary.
 

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