If using Debian testing or unstable:

	sudo apt-get install git-annex

git-annex is not yet in a Debian stable release, but the source
can be built from Debian stable. Just [[download]] it from git, and
then in the `git-annex` directory, run `dpkg-checkbuilddeps` and install
the necessary packages. You can also run `sudo debian/rules binary` to build
a `git-annex.deb`.