{"id":451,"date":"2022-02-25T04:39:09","date_gmt":"2022-02-25T04:39:09","guid":{"rendered":"http:\/\/miriamposner.com\/classes\/is270s23\/?page_id=451"},"modified":"2023-05-25T16:17:10","modified_gmt":"2023-05-25T16:17:10","slug":"getting-started-with-the-command-line-mac","status":"publish","type":"page","link":"http:\/\/miriamposner.com\/classes\/is270s23\/resources\/command-line-unix\/getting-started-with-the-command-line-mac\/","title":{"rendered":"Getting started with the command line"},"content":{"rendered":"\n

Every Mac comes equipped with a program called Terminal.<\/strong> This program allows you to communicate via typing with your Unix operating system. (Sometimes people call this using the command line.<\/strong>) <\/p>\n\n\n\n

PCs don’t use Unix operating systems, but you can download programs that allow you to interact with your computer in the same way. When you downloaded Git for Windows<\/a>, the download included a program called Git Bash<\/strong>, which will allow you to interact with your PC using textual commands, just like on Unix-based systems.<\/p>\n\n\n\n

Why would you want to do this? While graphical user interfaces (GUIs) are convenient, using the command line allows you to perform actions programmatically and to chain actions together so that, in many cases, you can perform a task much more quickly (or, in some cases, at all). Plus you look cool.<\/p>\n\n\n\n

You’ll hear the terms terminal, bash, shell, CLI, command line, and Unix used frequently (and often overlapping) to refer to this kind of work. Here’s an explanation of these terms<\/a>. For now, it’s really just important to know that we’re working in the shell.<\/p>\n\n\n\n

Before we get started, download t<\/a>his file<\/a> of sample data and decompress<\/strong> it. (On a PC, the process of decompression is called “extraction,” and here’s<\/a> how you do it.) Make sure you’ll be able to find the folder again later.<\/a><\/p>\n\n\n\n

1. Open your shell<\/h2>\n\n\n\n
\"Open<\/a><\/figure>\n\n\n\n

<\/p>\n\n\n\n

On a Mac: <\/h4>\n\n\n\n

To get started, use your computer’s search function (or press command<\/strong> and the space bar<\/strong>) and search for the terminal. (You can also open it by looking in your computer’s Utilities<\/strong> folder.)<\/p>\n\n\n\n

Then open it!<\/p>\n\n\n\n

On a PC: <\/h4>\n\n\n\n

Locate the program called Git Bash. If you kept all the default settings during installation, it should be available on your Start menu. If it’s not there, use your computer’s search function to locate Git Bash. Going forward, you’ll mostly see images of the Mac’s terminal, but these instructions should also work on Git Bash.<\/p>\n\n\n\n

On a Chromebook: <\/h4>\n\n\n\n

Please follow the instructions here<\/a>.<\/p>\n\n\n\n

<\/a>2. What are we looking at?<\/h2>\n\n\n
\n
\"What<\/a>
Terminal on a Mac<\/figcaption><\/figure>\n<\/div>\n\n\n

This is a terminal window, also called a shell! It has a command prompt<\/strong> waiting for you to tell it what to do. You can tell it’s waiting for you to type something because it displays a %<\/strong> (or a $<\/strong>, they mean the same thing).<\/p>\n\n\n\n

To work in the shell, you’ll type out a command and then press return. Let’s try our first command. Type<\/p>\n\n\n\n

whoami <\/code><\/pre>\n\n\n\n
and press return<\/strong>. The terminal returns your username. (Mine’s miriamposner.)<\/p>\n\n\n\n
And now the command prompt displays again, ready for you to issue your next instruction. <\/p>\n\n\n\n
(You don’t need to delete previous commands; you can just keep going, and as you go, you’ll be able to scroll backwards to see what you’ve already typed.)<\/p>\n\n\n\n
<\/a>3. Say hello<\/h2>\n\n\n\n
\"Say<\/a><\/figure>\n\n\n\n
This is another easy one. Type<\/p>\n\n\n\n
echo 'Hello world'<\/code><\/pre>\n\n\n\n
and press return. The command echo<\/strong> instructs the terminal to repeat whichever characters you include in the quotation marks.<\/p>\n\n\n\n
Great! Now you should see the command prompt again.<\/p>\n\n\n\n
<\/a>4. Getting around in the terminal<\/h2>\n\n\n\n
\"Getting<\/a><\/figure>\n\n\n\n
As you’ve probably already noticed, you can’t do too much in the terminal using your mouse. Instead, the terminal awaits typed commands. Here are some keyboard shortcuts that may make your life a little easier:<\/p>\n\n\n\n
Use the up and down arrows<\/strong> on your keyboard to move back (up) and forward (down) through the previous commands you typed. This often saves you typing. Try pressing the up arrow once to rewind to the echo<\/strong> command you typed earlier. Then use the left and right arrows to delete the current contents of the quotation marks, replacing them with whatever you want. Then press return<\/strong>.<\/p>\n\n\n\n