git-gui
A GUI for Git to manage branches, commits, and remotes, and perform local merges.
TLDR
Launch the GUI
$ git gui
Show a specific file with author name and commit hash on each line
$ git gui blame [path/to/file]
Open git gui blame in a specific revision
$ git gui blame [revision] [path/to/file]
Open git gui blame and scroll the view to center on a specific line
$ git gui blame --line=[line] [path/to/file]
Open a window to make one commit and return to the shell when it is complete
$ git gui citool
Open git gui citool in the "Amend Last Commit" mode
$ git gui citool --amend
Open git gui citool in a read-only mode
$ git gui citool --nocommit
Show a browser for the tree of a specific branch, opening the blame tool when clicking on the files
$ git gui browser maint