Software > Text editors >

(on Wikipedia)
https://www.kdevelop.org/

An IDE.

I never used it. It’s just here for reference.

Ruby support ∞

Has integrated support for Ruby, but it’s incomplete.

https://developers.slashdot.org/story/04/12/06/1158251
KDE’s award winning integrated development environment KDevelop, has integrated support for Ruby.

Ruby really isn’t supported very well it seems: https://web.archive.org/web/20040806121452/http://www.kdevelop.org/HEAD/doc/api/html/LangSupportStatus.html