grepWin - grepWin is a simple search and replace tool which can use PCRE regular expressions to search for...

RegExr - RegExr.com is an online tool to learn, build, and test Regular Expressions.

grep - grep is a command-line utility for searching plain-text data sets for lines matching a regular...

Expresso - The award-winning Expresso editor is equally suitable as a teaching tool for the beginning user of regular expressions or as a full-featured development environment for the experienced programmer with an extensive knowledge of regular expressions.

dnGREP - dnGrep allows you to search across files with easy-to-read results.

rubular - A ruby based regular expression editor