pwd

Prints the name of your current working directory.

ls

Lists all the content of your current working directory.

cd

You move from your current working directory to your user's home directory. Note: cd stands for change directory.

cd test_dir
You move to the test_dir directory - if test_dir exists in your current working directory.

cd ..
Moves up one folder.

cd -
Moves to the folder where you previously were.

mkdir one_more_dir
Creates a new directory called one_more_dir.