Git Add/Commit (gac) is a command I started with as a small alias and evolved into what it is now, a slick script that simplifies my git interactions.
brew install flare576/scripts/gac
My most common usages are
gac -a # amend previous commit after adding all changes
gac -f my.js src/firstSet.js tests/ofChanges # Create new commit using the files listed
gac # Create new commit after adding all changed files
gac -u # ignore untracked files during add/commit