git-repl
Git REPL (read-evaluate-print-loop) - an interactive Git shell.
TLDR
Start an interactive Git shell
$ git repl
Run a Git command while in the interactive Git shell
$ [git_subcommand] [command_arguments]
Run an external (non-Git) command while in the interactive Git shell
$ ![command] [command_arguments]
Exit the interactive Git shell (or press Ctrl + D)
$ exit