cd -
Back to the previous directory — and it even announces where it went.
The shell keeps the previous directory in OLDPWD, and cd - goes back there, printing the destination. Called again, it goes back again: a shuttle between two points.
It is the right displacement for whoever alternates between two territories — the code and the logs, the project and the test. For longer trails, the drawer keeps pushd.
$ pwd
/home/ana/ninho
$ cd /var/log
$ cd -
/home/ana/ninho