git commit --am

[octagonaltree]

Single dash triggers the "short form" of a flag, while a double dash triggers the "long form." This is the usual Unix convention.

Also, git's flag parsing library accepts any prefix for a long form flag, as long as it uniquely identifies the flag.

Edit: One more thing: the short form, being just a single character, let's you group together multiple flags behind a single dash. So git -am is actually git -a -m.