(grep.info.gz) Regular Expressions

Info Catalog (grep.info.gz) Invoking (grep.info.gz) Top (grep.info.gz) Usage
 
 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 the 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 the pcresyntax(3) and
 pcrepattern(3) manual pages, but may not be available on every system.
 

Menu

 
* Fundamental Structure
* Character Classes and Bracket Expressions
* The Backslash Character and Special Expressions
* Anchoring
* Back-references and Subexpressions
* Basic vs Extended
 
Info Catalog (grep.info.gz) Invoking (grep.info.gz) Top (grep.info.gz) Usage
automatically generated by info2html