When you run git diff on most systems, the viewer seems to be more, i.e. the diff stays in the terminal after exiting. On a system I’m on it seems like less is the default. My ~/.gitconfig currently has no entry that specifies this. How do I check what viewer is used, and how do I change it?

I found info about git difftool and external diff editors etc, but this is not what I’m looking for, I just want normal git diff settings.