ColdFISH is developed by Jason Delmore. Source code and license information available at coldfish.riaforge.org diff /path/to/project/index.cfm /path/to/project/index.cfm | mate1diff /path/to/project/index.cfm /path/to/project/index.cfm | mate
This comes in really handy when you are using Git on the command-line as well. When you do git diffs you can pipe it the same way and the result is really nice and readable since Textmate has color coding support for diffs.