Go back to previous directory in shell

cd - (goes back to previous directory)

If you want to be able to go to the other previous directories, this is not possible out of the box. But check this script and instructions:

History of visited directories in BASH

The cd command works as usual. The new feature is the history of the last 10 directories and the cd command expanded to display and access it. cd -- (or simply pressing ctrl+w) shows the history. In front of every directory name you see a number. cd -num with the number you want jumps to the corresponding directory from the history.

You can also use variable cd $OLDPWD. This can be also used in shell scripts.