Unix Tutorial #1: Navigating the directory tree¶
Note
Topics covered: Directories, navigation
Commands used: pwd, cd, ls
Overview¶
Like other operating systems, Unix organizes folders and files using a directory tree - also known as a directory hierarchy, or directory structure. At the top of the hierarchy is a folder called root
, written as a forward slash (/
). All other folders (also known as directories) are contained within the root
folder, and those folders in turn can contain other folders.
Think of the directory hierarchy as an upside-down tree: root
is the base of the tree, and all of the other folders extend from it, just as branches extend from the trunk.

Root, symbolized by a forward slash (/
), is the highest level of the directory tree; it contains folders such as bin
(which contains binaries, or Unix commands such as pwd, cd, ls, and so on), mnt
(which shows any currently mounted drives, such as external hard drives), and Users
. These directories in turn contain other directories - for example, Users
contains the folder andrew
, which in turn contains the Desktop
, Applications
, and Downloads
directories. This is how folders and files are organized within a directory tree.
To navigate around your computer, you will need to know the commands pwd
, cd
, and ls
. pwd
stands for “print working directory”; cd
stands for “change directory”; and ls
stands for “list”, as in “list the contents of the current directory.” This is analogous to pointing and clicking on a folder on your Desktop, and then seeing what’s inside. Note that in these tutorials, the words “folder” and “directory” are used interchangeably.

Navigation in Unix is the same thing as pointing and clicking in a typical graphical user interface. For example, if you have the folder “ExperimentFolder” on my Desktop, you can point and double-click to open it. You can do the same thing by typing cd ~/Desktop/ExperimentFolder
in the Terminal and then typing ls
to see what’s in the directory.
Video¶
Click here to see a video overview of the commands cd, ls, and pwd - the basic commands you will need to navigate around your directory tree.
Exercises¶
When you’re done watching the video, try the following exercises:
- Type
ls ~
and note what it returns; then typels ~/Desktop
. How are the outputs different? Why? - Navigate to the Desktop by typing
cd ~/Desktop
. Typepwd
and note what the path is. Then create a new directory using themkdir
command, choosing a name for the directory on your own. Navigate into that new directory and think about how your current path has been updated. Does that match what you see from typingpwd
from your new directory? - Define the terms
cd
,ls
, andpwd
in your own words.