In OSX Bash you could use to autocomplete file paths. You can also use My Dotfiles to get tab completion for SSH hostnames based on ~/.ssh/config and many more commands.

You need to get the .git-completion.bash from Repository or you cand use this command in your terminal:

curl -o ~/.git-completion.bash

Then you need to update your .bash-profile file with:

if [ -f ~/.git-completion.bash ]; then
  . ~/.git-completion.bash

Now you need to restart your terminal and after you type git c then hit TAB key you can see all the git commands that start with c letter.

Git Tab Autocompletion

How to make it work with aliases

Let’s say you have aliases for:

alias g ='git'
alias gco = 'git checkout'

You can use __git_complete function from git-completion.bash which can be used to set up completion for aliases. Update your .bash-profile file with:

if [ -f ~/.git-completion.bash ]; then
  . ~/.git-completion.bash

  # Add git completion to aliases
  __git_complete g __git_main
  __git_complete gco _git_checkout