====== How to Use Regular Expressions ======

A regular expression is a search string that uses special characters to match patterns of text. You can use them as with the Find command, as with the Replace command in conjunction with replacement expressions.

===== Summary of regular expressions: =====

^ Operator ^ Description                ^
| %%^%%    |Match the beginning of line|
| $        |Match the end of line|
|,|Match any character|
|[]|Match characters in set|
|[%%^%%]|Match characters not in set|
|?|Match previous pattern 0 or 1 times (greedy)|
|%%|%%|Match previous or next pattern|
|*|Match previous pattern 0 or more times (greedy)|
|+|Match previous pattern 1 or more times (greedy)|
|{}|Group characters to form one pattern|
|()|Group and remember|
|\|Quote next character (only of not a-z)|
|\<|Match beginning of a word|
|\>|Match end of a word|
|\x%%##%%|Match character with ASCII code %%#%% (hex)|
|\x####|Match Unicode character with ASCII code %%##%% (hex)|
|\o###|Match ascii code|
|\a|Match \a|
|\r|Match 0x13 (cr)|
|\b|Match \b (but only inside a character class declaration)|
|\t|Match 0x09 (tab)|
|\f|Match \f|
|\v|Match \v|
|\n|Match 0x10 (lf)|
|\e|Match escape (%%^%%E)|
|\s|Match white space (cr/lf/tab/space)|
|\S|Match nonwhite space (!\S)|
|\w|Match word character|
|\W|Match non-word character|
|\d|Match digit character|
|\D|Match non-digit character|
|\u|Match uppercase|
|\U|Match non-uppercase|
|\l|Match lowercase|
|\L|Match non-lowercase|
|\C|Match case sensitively from here on|
|\c|Match case ignore from here on|
|[[http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html|Other operators...]]||
   

HippoEDIT uses regular expression engine from BOOST library. So further information about possible flags, syntax and examples can be found on [[http://www.boost.org/doc/libs/1_50_0/libs/regex/doc/html/boost_regex/syntax/perl_syntax.html|BOOST website]].

For examples of regular expression you can check [[http://regexlib.com/|Regular Expression Library]]

For testing your regular expression try this great resource: [[http://gskinner.com/RegExr/|Regexr]]

A desktop version of this tool is also available: [[http://www.gskinner.com/RegExr/desktop/|Desktop Regexr]]