Does the prompt you get give you the option of 'run in a terminal'? If so, try that - though even if that works, it is not ideal.
The problem might be to do with file associations - because/or something to do with java. Have you read these instructions?
> The gui is very limited
It can not be stressed enough that there is no "the" GUI. I use SmartGit (cross platform, commercial use is not free) and I think the only thing I've ever needed to do that it can't handle is creating an orphan commit - but that's about it.
> I don’t know for sure because I am so used to use the command line for git. But I think git doesn’t have a gui in Linux.
https://www.syntevo.com/smartgit/ or https://tortoisegit.org.
The tools are developed by third parties but highly recommended if you want to use a GUI.
>Let me know what you use, thanks!
Sometimes i use TortoiseHg as I don't use git. However, there is also a version for git (https://tortoisegit.org).
As for git, I consider SmartGit not bad.
Yes, however I couldn't stand the notifications about background refresh (every few minutes, and it's impossible to disable).
Another good GUI client that I personally use, but that doesn't feel really native/polished as gittower is smartgit - which is also free for non-profit use.