Committing without opening an editor

Git will usually open an editor (like vim or emacs) when you run git commit. Pass the -m option to specify a message from the command line:

git commit -m "Commit message here"

Your commit message can go over multiple lines:

git commit -m "Commit 'subject line' message here

More detailed description follows here (after a blank line)."

Alternatively, you can pass in multiple -m arguments:

git commit -m "Commit summary" -m "More detailed description follows here"

See How to Write a Git Commit Message.

Udacity Git Commit Message Style Guide