(grep) Regular Expressions
3 Regular Expressions
A "regular expression" is a pattern that describes a set of strings.
Regular expressions are constructed analogously to arithmetic
expressions, by using various operators to combine smaller expressions.
`grep' understands three different versions of regular expression
syntax: "basic," (BRE) "extended" (ERE) and "perl". In GNU `grep',
there is no difference in available functionality between basic and
extended syntaxes. In other implementations, basic regular expressions
are less powerful. The following description applies to extended
regular expressions; differences for basic regular expressions are
summarized afterwards. Perl regular expressions give additional
functionality, and are documented in pcresyntax(3) and pcrepattern(3),
but may not be available on every system.
* Fundamental Structure
* Character Classes and Bracket Expressions
* The Backslash Character and Special Expressions
* Back-references and Subexpressions
* Basic vs Extended
automatically generated by