KLayout is a free open source layout editor. The Red Toolbox (TRT) is a set of scripts that run on KLayout to provide useful functions. Try it out!
To install, copy this folder structure to your 'macros' directory. so all the subfolders will be inside C:\User\username\KLayout\macros\The Red Toolbox, or similar for linux. Restart KLayout and look for the TRT menu at the top. If you have a previous version installed, delete that TRT folder and replace it with the new one.
Also try Examples...