Lab 0: Getting Started (Mac/Linux Setup)

Walkthrough: Organizing Your Files

In this section, you will learn how to manage files using terminal commands. Start by opening your terminal.

Make sure your prompt contains a $ or % somewhere in it and does not begin with >>>. If it begins with >>> you are still in a Python interpreter, and you need to exit. See above for how.

Directories

The first command you'll use is ls. Try typing it in your terminal:

ls

The ls command (which stands for list) lists all the files and folders in the current working directory. Recall that "directory" is another name for a folder (such as the Documents folder).

Since your working directory is the home directory right now, after you type ls you should see the contents of your home directory.

CLI vs GUI

Remember that you can access the files and directories (folders) on your computer in two different ways. You can either use the terminal (which is a command line interface or CLI) or you can use Finder. Finder is an example of a graphical user interface (GUI). The techniques for navigating are different, but the files are the same. For example, here's how my lab folder looks in my GUI:

And here's how the exact same folder looks in terminal:

Notice the yellow box shows you the path in both cases, and the purple ellipse shows you the contents of the "labs" folder.

Changing Directories

To move into another directory, use the cd command (which stands for change directory). cd takes in a path as input and changes the working directory of your terminal to be directory identified by that path.

Let's try moving into your Desktop directory. First, make sure you're in your home directory (check for the ~ on your command line) and use ls to see if the Desktop directory is present.

Try typing the following command into your terminal, which should move you into that directory:

cd Desktop

If you're not already in your home directory, try cd ~/Desktop. This is telling the terminal the path where you want to go.

Making New Directories

Once you're in the Desktop directory, the next command is called mkdir, which stands for make a new directory. mkdir takes in a name as input and creates a new directory with that name. The new directory is stored in the current working directory.

Let's make a directory called cs61a in your Desktop directory to store all of the assignments for this class:

mkdir cs61a

A folder named cs61a will appear on your Desktop. You can verify this by using the ls command again or by checking your Desktop using Finder.

At this point, let's create some more directories. First, make sure you are in the cs61a directory (~/Desktop/cs61a). Then, create three new folders called projects, lab, and hw. All of them should be inside of your cs61a folder:

cd ~/Desktop/cs61a
mkdir projects
mkdir lab
mkdir hw

Now if you list the contents of the directory (using ls), you'll see three folders, projects, lab, and hw.

More Directory Changing

There are a few ways to return to the home directory:

• cd .. (two dots). The .. means "the parent directory", or one directory above your current directory.
• cd ~ (the tilde). Remember that ~ means home directory, so this command will always change to your home directory.
• cd (cd on its own). Typing just cd is a shortcut for typing cd ~.

You do not have to keep your files on your Desktop if you prefer otherwise. Where you keep your files locally will not affect your grade. Do whatever is easiest and most convenient for you!

Downloading the Assignment

If you haven't already, download the zip archive, lab00.zip, which contains all the files that you'll need for this lab. Once you've done that, let's find the downloaded file. On most computers, lab00.zip will probably be located in a directory called Downloads in your home directory. Use the ls command to check:

ls ~/Downloads

If you don't see lab00.zip, ask for help on EdStem or in office hours. On some versions of Safari the file may get unzipped for you, in which case you would just see a new directory named lab00.

Extracting Starter Files

You must expand the zip archive before you can work on the lab files. Different operating systems and different browsers have different ways of unzipping. Clicking on a .zip file in Mac will automatically unzip. If you run into trouble, you can search online for how to unzip a file.

Here's a way to unzip using the terminal:

Using a terminal, you can unzip the zip file from the command line. First, cd into the directory that contains the zip file:

cd ~/Downloads

Now, run the unzip command with the name of the zip file:

unzip lab00.zip

You only need to unzip the files once.

Once you unzip lab00.zip, you'll have a new folder called lab00 which contains the following files (check it out with cd lab00 and ls):

• lab00.py: The template file you'll be adding your code to
• ok: A program used to test and submit assignments
• lab00.ok: A configuration file for ok

Moving Files

Move the lab files to the lab folder you created earlier:

mv ~/Downloads/lab00 ~/Desktop/cs61a/lab

The mv command will move the ~/Downloads/lab00 folder into the ~/Desktop/cs61a/lab folder. If you prefer, you can also move the file by dragging and dropping it into the correct folder in your graphic file explorer, which is probably more familar and will have exactly the same result.

Now, go to the lab00 folder that you just moved. Try using cd to navigate your own way! If you get stuck, you can use the following command:

cd ~/Desktop/cs61a/lab/lab00

Summary

Here is a summary of the commands we just went over for your reference:

• ls: lists all files in the current directory
• cd <path to directory>: change into the specified directory
• mkdir <directory name>: makes a new directory with the given name
• mv <path to source> <path to destination>: moves the source file/directory into the destination directory

The exams for this course will not test you on how the file system works, what the definition of an absolute path is, or what commands you use in the terminal. However, these skills are essential for completing all of the assignments in this course. You can reference this page in the future.

Finally, you're ready to start editing the lab files! Don't worry if this seems complicated—it will get much easier over time. Just keep practicing! You can also take a look at our UNIX tutorial for a more detailed explanation of terminal commands.