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.

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
\aMatch \a
\rMatch 0x13 (cr)
\bMatch \b (but only inside a character class declaration)
\tMatch 0x09 (tab)
\fMatch \f
\vMatch \v
\nMatch 0x10 (lf)
\eMatch escape (^E)
\sMatch white space (cr/lf/tab/space)
\SMatch nonwhite space (!\S)
\wMatch word character
\WMatch non-word character
\dMatch digit character
\DMatch non-digit character
\uMatch uppercase
\UMatch non-uppercase
\lMatch lowercase
\LMatch non-lowercase
\CMatch case sensitively from here on
\cMatch case ignore from here on
Other operators...

HippoEDIT uses regular expression engine from BOOST library. So further information about possible flags, syntax and examples can be found on BOOST website.

For examples of regular expression you can check Regular Expression Library

For testing your regular expression try this great resource: Regexr

A desktop version of this tool is also available: Desktop Regexr