Notepad++
For Windows, Mac, Linux. Supports many languages right out of the box.Get it from https://notepad-plus-plus.org/download/
Compare (Diff) PlugIn
I don't use any of the plugins, except for the Compare (Diff) plugin. Gives you a nice text diff of two files.
Compare does not come with Notepad++, you have to download it separately. The Readme instructions are a little sparse about installing. Basically you just put the .DLL (Windows) or other OS files in the Notepad++ plugins/ directory. e.g. 64-bit Windows it goes in C:\Program Files (x86)\Notepad++\plugins
Download it from https://sourceforge.net/projects/npp-compare/
=SWGun.Slingers[1];