(gawk.info.gz) Regexp
Info Catalog
(gawk.info.gz) Invoking Gawk
(gawk.info.gz) Top
(gawk.info.gz) Reading Files
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'. Therefore, the
pattern `/foo/' matches any input record containing the three
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 `[...]'.
* GNU Regexp Operators Operators specific to GNU software.
* Case-sensitivity How to do case-insensitive matching.
* Leftmost Longest How much text matches.
* Computed Regexps Using Dynamic Regexps.
Info Catalog
(gawk.info.gz) Invoking Gawk
(gawk.info.gz) Top
(gawk.info.gz) Reading Files
automatically generated by
info2html