Also, if you are an Emacs user, its VC package is very powerful. For example, `C-x v g` to bring up the "blame" (vc-annotate) view, in which you can (for any commit) press `a` to see what the file looked like before that commit, `d` to see the diff of the commit, `l` to see the commit message... That's just the tip of the iceberg of things you can do with it. It supports Git, Mercurial, Bazaar, CVS, Subversion and more as a backend.

https://www.emacswiki.org/emacs/VersionControl