This tool uses the Microsoft VB Scripting RegEx control to allow searching and optionally replacing text using regular expressions. Regular expressions allow searching for patterns instead of just specific text. Different RegEx implementations use varying syntax. The allowed syntax is displayed in the main window of this utility.
This utility comes with an installer, but it is also designed to be portable. Just copy regex.exe after installation, or extract the file from the setup exe using an unzip tool. In the options menu you can choose to save settings to an INI file (default) or the registry.
Although there are other text editors like NotePad++ that support regular expressions, I have not found a tool that is simple, designed just for building/using regular expressions, that supports VB Scripting syntax, that displays the syntax documentation while you're editing, that allows replacing using submatches, and that is free...so I wrote one.
RegEx Search & Replace is open source freeware. You can download it from my website http://tribblesoft.com/RegEx.php
The VB6 runtime libraries are required to run this, but they've come with Windows since Windows 2000, and most PCs with Windows 98 or 95 have them installed anyway so that should not be a problem for most people.
I hope you find this useful. I welcome your comments and suggestions.