∙ File system navigation
Understanding where you are, and how to move around
Where am I?
Let’s run our first command!
pwd
With pwd we are asking “print my current working directory / where am I?” You will then get some output to the terminal window, something like
/home/at9362
This is your current location, here shown as a “path” - what folder you are in, starting from the “root” folder that contains the whole file system.
There are five abbreviations for locations that you might come across
~“tilde”, your home folder.“dot”, your current working folder..“dot dot”, one folder “up” or “back” from here-“dash”, the folder you were most recently in/“root”, the folder containing the whole file system
What is in this folder?
Now that we know where we are, let’s see what is here by running a program called ls (“list” or “ell ess”). ls shows you the contents of your current folder, much like looking at the file manager window in a GUI (Finder in MacOS or Explorer on Windows):
ls
For me, I get this output, a list of what is here.
logfile records_january credentials.txt creds data_depot git
Yours will be different. Each of these things are the items (files and folders) in your current working directory. For most terminals, items in white are files, and items in blue are folders. The first thing we are going to do is make a new folder, where we will be doing our work. We will use the command mkdir (“make directory”), and this command needs an argument (gramatically, an “object”):
Making our first folder.
Let’s create a folder where we can learn how to move around.
mkdir intro-to-command-line
This command is asking “make a new folder here, called intro-to-command-line”. You’ll be getting used to the names of commands being abbreviations! Run ls again, and see what has changed. Hopefully you will see a new folder, appropriately named.
We can then move into the folder we have made with
cd intro-to-command-line
Here we are asking to “change my working folder to intro-to-command-line”. This is the same as double-clicking a folder in your GUI, to move into that folder. Try doing ls and pwd here, to see how the output changes. We can go back to your home folder by going
cd ..
This means “change folder to the one above this one”. Going cd .. will always move you “backwards” in your folders, unless you are in the root folder /. If you are ever lost, remember you can just go cd to go back to your home folder.
cd .. as above,
cd -, and just
cdExercise
cd alone will always take you back to your home folder. Try repeating cd .., and do ls each time.
- Where do you end up if you do this several times?
- What is there?
- Can you return to the folder you named
intro-to-command-line, using its absolute path?
If you end up in a folder called /, you are in the “root” folder.
This folder contains the whole file system of the machine you are working on.
You might find mysterious folders called things like opt, etc, tmp. Don’t worry about these things for now! They are just folders holding the components of your operating system.
Move back to your folder intro-to-command-line. From this point forward, we will be working with the course materials (this is the same file as linked on the home page of this course). Download this file, and using your GUI, move this file into the folder we made in the last section. This might be in your home folder, or your desktop - it doesn’t matter where, as long as it makes sense to you! Then unzip the file - double click it, or right-click and “open” it. You will then have a new folder called command_line_files.
If you are working on Windows, run this command (since you are using GitBash, we can directly clone the files)
git clone https://github.com/alleetanner/intro-to-command-line.git
Using cd, move into the folder called sandpit. From here, look around using ls, move around using cd, and see what is in each folder.