You give us a regex and we'll show you what it matches.

Test ruby regular expressions

headache relief for programmers :: regular expression generator

a Ruby regular expression editor

Anti-rant: Jeff Atwood *loves* regexp, as long as they're used appropriately.

Here are just some of the powerful features available:
 
Immediate results   Found text is shown with highlighted keywords so you don't need to waste time opening each file looking for the right information.
 
Boolean expressions   Combine search terms using the familiar Boolean operators AND, OR, NOT.
 
Office formats   Support for popular Office formats including Office 2007 and OpenOffice.
 
Perl regex   Support for Perl compatible regular expressions.
 
64-bit Version   Natively compiled 64-bit version for improved compatibility.
 
Fast searching   Highly efficient search algorithms mean that you spend less time waiting for results.
 
Printing and Exporting   Results can be shared with others through printing and exporting.