Getting Started With the Terminal

I’d like to thank the redditors over at r/learnprogramming for their suggestions to this article.

So, you want to learn how to use the Terminal. Great! As a developer, sooner or later, you’ll want to learn how to use the Terminal. Not only is this a handy tool to have under your belt, but it will also boost your productivity.

Table of Contents

Before Starting

While most of the commands I'll be talking about apply to both Mac and Linux, this article was written assuming you're using a Mac. Therefore, some commands, like the open command, may not work if you're using Linux.

Now, before actually getting started learning commands, it’s useful to think of the directories (folders) as a hierarchical tree.

1.png
The root directory is “/” and inside of “/”, you have the following folders: bin, tmp, usr, and src.

In the illustration above, you can see that the first directory, often referred to as the “root” directory, is named “/”. That directory (folder) contains other directories such as bin, tmp, usr, and src. Those directories can have other directories or files and those child directories can have even more directories or files and so on.

Of course, the illustration above is just an example, it doesn’t actually reflect the folders and files that reside in your computer.

Now, what the terminal allows us to do is to traverse and manage the directory tree. This is why the terminal is so powerful, it allows us to quickly sift through folders and files in an efficient manner as well as being able to create, delete, or update a file or directory.

Opening Your Terminal

To open your terminal, use the following shortcut: + Spacebar. Now type in "Terminal" and then press the Enter key.

Now, you should have something on your screen that looks like

2.png

For the most part, you should be staring at a black window with white text and a cursor itching for your next command.

Important Notes

It’s important to note that every directory on Mac/UNIX/LINUX has two hidden directories, namely “.” and “..”

The “.” means the current directory and “..” means previous or parent directory. Keep this in mind, it will be useful later.

Don't worry if you don't understand what the commands in the following screenshots do quite yet, just take note of the tab and arrow key functionality.

Another thing, when you type a command, path, or filename, you can use "tab" to auto-complete the name.

tab-auto-complete.gif
Tab auto-completion.

You can also cycle through your previous commands with the arrow ↑ and arrow↓ keys. In addition, you can use the arrow ← or arrow → to move the cursor.

up-down-left-right.gif
Arrow key functionality.

Now, the actual program you will be interacting with is called the shell.

The following doesn't affect the commands we'll be going over but if you plan on writing shell scripts, make a note of which shell you are going to use. There are many shells but the most common one is BASH (Bourne-Again SHell). This used to be the standard for Apple but now they have upgraded to ZSH (Z-SHell).

Commands

Now that we have a terminal window in front of us, it’s finally time to get to the commands.

The first command you should type into the terminal should be the pwd (print working directory) command.

pwd — print working directory
pwd

This command prints the current directory you’re in onto the terminal.

3.png
Currently in the “/Users/alanconstantino” directory.

Congratulations, you just ran your first command on the terminal!

This command is useful for knowing where you currently are within the directory tree.

The next command we should try is ls or list.

ls - list
ls

This command lists all the directories and files from your current directory.

4.png
By typing ls, we can see all of the files and directories within the current directory.

Cool, now we can list all of the files and directories from our current directory.

But what if we want to list all the contents from another directory?

Simple, just type the following command:

ls [directory name]
5.png
We list all the files and folders inside of the “Desktop” directory.

Now we can list files and folders from our current directory or other directories.

We can also list hidden files with the "-a" option:

ls -a

All the "-a" option means is to show all files including the ones that start with the "." prefix also known as hidden files.

A hidden file or directory is just like a normal file or directory except it starts with the "." prefix and is hidden from the user.

It's also important to keep in mind that most, if not all commands can have options and there are different options for every command. You can also have multiple options in one command.

Now, notice in the following screenshot how just doing the ls command doesn't show hidden files but when we add the "-a" option, it will list everything including hidden files.

hidden-files.png
Listing hidden files with the "-a" option.

As you can see, in the directory named "example" we have a hidden file named ".myfile.txt" and a hidden directory named ".mydirectory."

As you may recall from earlier, "." means our current directory and ".." means our parent directory. Every folder within your Mac/UNIX/Linux machine contains these two extra hidden files.

Moving on from the ls command, what if we want to change our current directory? That's where the cd or change directory command comes into play.

cd — change directory
cd [directory name]

The cd command allows you to change your directory to another directory. This is how you’ll actually traverse the directory tree.

Example:

cd /

The command above changes your current working directory to your root directory.

6.png
“cd /” changes your current directory to your root directory.

Another useful cd command to keep in mind is

cd ~

which changes your current directory to your home directory like so:

cd ~.png
We are now in the home directory.

Now, how do we back out of a directory or go to the previous/parent directory?

We have to use the following command:

cd ..

As I mentioned earlier, the “..” means the parent directory or previous directory. Effectively, the command above is telling the terminal “Hey, take me back to the previous directory.”

7.png
Changed directory from “/Users/alanconstantino/Desktop” to “/Users/alanconstantino.”

Also, if you use this command in the root directory, nothing happens because there isn’t a previous or parent directory to go back to, hence the name root.

But what if you want to go back more than one directory?

No problem, the following command is just what you need.

cd ../../

The command above tells the terminal “Hey, I want to go back two directories and make it snappy.” Okay, maybe not so much the snappy part, but it does take you back two directories.

Essentially, every “../” you add takes you back one directory.

So the following example will take you back three directories:

cd ../../../

Finally, another useful-to-know "cd" command is

cd -

With the above command, you'll return to your previous working directory.

So for example, let's say I was in the

/Users/alanconstantino/Desktop/

directory. Then I navigate to

/Users/alanconstantino/Desktop/myFolder/anotherFolder/

If I do the "cd -" command, I'll be back at

/Users/alanconstantino/Desktop/

If I type in the "cd -" command once more, I'll be at the

/Users/alanconstantino/Desktop/myFolder/anotherFolder/

Now that we know how to traverse the directory tree and list its contents, we should move onto more useful commands.

Before that though, we should probably clear our terminal screen because by now it may be a little tough to read.

clear

By typing in the following command into the terminal, you are able to clear what’s on screen.

clear
8.gif
Clearing the terminal.

Now that our screen has been cleared, we can move onto more useful commands, like the mv (move) command.

mv - move
mv [source] [destination]

The mv (move) command has two uses, the first is just as the name implies, you can move things from one place to another. The second use is for renaming a file.

Lets' take a look at the former.

From the skeleton command above, the “source” is what you want to move while the “destination” is where you want the file to end up.

For example, if I have something like the following:

one
├── myfile.txt
└── two

Where “one” and “two” are folders, and I want to move, “myfile.txt” to folder “two” I would simply do the following assuming I was already in the “one” folder location:

mv myfile.txt two
9.png
We moved “myfile.txt” to the folder “two.”

Of course, you could be anywhere in the directory tree to execute this command — and pretty much any command for that matter — but you just have to make sure you enter the full location path of the file you want to move and its destination.

For example, in the following screenshot, I’m in my root directory but I’m still able to move a file from my Desktop to the “two” folder from the previous example:

10.png
We moved “anotherfile.txt” to the “two” folder while in the root directory.

Now, what if we wanted to move a file or folder from wherever it is to our current location in the directory tree.

Well, remember earlier how I talked about the “.” being our current directory, we would have to use “.”

For example:

mv /somelocation/myfile.txt .

The example above moves “myfile.txt” to wherever we currently are in the directory tree.

Now let's take a quick look at the second use of the mv command which is for renaming files.

To rename a file, you can do the following:

mv [old file name] [new file name]

So if I have a file called "myfile.txt" and I want to rename it to something else, I would do the following:

mv myfile.txt newname.txt

And that's it! Now "myfile.txt" gets renamed to "newname.txt."

Another command that’s similar to mv (move) is cp (copy).

cp — copy
cp [source] [destination]

The copy command is just like the move command except instead of moving a file or folder, it makes a copy of it leaving the original file unharmed.

To copy a file you would do the following:

cp myfile.txt /one
11.png
We copied “myfile.txt” to the “one” folder.

Now to copy a directory you have to add the “-r” option like so:

cp -r one two
12.png
We copy the contents of the “one” directory into the “two” directory.

All the “-r” option means is that it tells the terminal to copy the files recursively which is a fancy way of saying everything.

So by using the “-r” option, we tell the terminal “Please copy all the contents, including folders and files to our destination.”

Now, what if we wanted to open a file or folder from our terminal?

We would need to utilize the open command.

open

Note: The Linux equivalent of this command seems to be "xdg-open" but this may differ from distro to distro.

open [file/folder]

This command lets us open a file with its associated program.

For example, if we have a “.txt” file and we do the following command:

open myfile.txt
13.png
We open a file named “myfile.txt.”

this opens “myfile.txt” with your default text editor like so:

14.png

Here’s another example.

If you do the following command, it will open the finder window in the root directory.

open /
15.png
We opened a new finder window at the root directory.

The finder window will look something like the following:

16.png
A finder window showing the contents of the root directory.

It opens the finder window because that’s the program that is associated with the file or in this case the folder you’re trying to open.

So if we did the following command:

open .

it would open a new finder window from our current location because remember, the “.” means our current directory.

Now, let’s move onto actually making a directory from the terminal.

mkdir — make directory
mkdir [directory name]

To make a directory, you simply type the command above and give it a name like so:

17.png
We made a directory named “mydirectory.”

We can also create multiple directories like so:

18.png
We created two directories, one named “newdirectory” and another named “anotherdirectory.”

What if we wanted to make a file instead of a directory?

We would use the touch command.

touch
touch [file name]

This command has two uses but I'll only talk about its main use and mention the second.

Its main use is for creating an empty file.

Its other use is for updating timestamps of a file but we won't get into that for the sake of simplicity.

So if we do the following:

touch myfile.txt

This creates a file named “myfile.txt” in our current directory.

19.png
We create a file named “myfile.txt.”

And similar to mkdir, you can create multiple files in one command like so:

20.png
We create “myfile.txt” in the current directory and “anotherone.txt” in the previous directory.

In the screenshot above, we create two files, “myfile.txt” and “anotherone.txt.”

The “myfile.txt” file is created in the current directory while the “anotherone.txt” file is created in the previous directory.

Let’s move on to deleting a directory.

rmdir — remove directory
rmdir [directory name]

The rmdir command is self-explanatory, it just deletes a directory.

21.png
We are deleting an empty directory named “emptydir.”

However, it’s important to note that when using this command, you can only remove an empty directory.

If your directory is not empty and you try to use the rmdir command, you’ll get something like the following:

22.png
We failed at removing the directory “folder” because it’s not empty.

Now how do we remove the contents of a directory you may be asking?

We would have to use the rm (remove) command.

rm — remove
rm [file name]

This command is probably the most powerful and yet the most dangerous one on this list which is why I saved it for last.

Once you use this command and delete something, it’s gone forever.

It doesn’t get put into your Trash for you to empty out later. No! Once you type in this command and hit enter, poof… it’s gone… forever…

This also applies to rmdir, once you remove a directory, it’s gone forever.

But unlike rmdir, the rm command has the ability to remove both a directory as well as a file which makes this command better than rmdir.

With this in mind, let’s see it in action.

To remove a file, simply do the following:

rm myfile.txt
23.png
We removed a file named “myfile.txt.”

And just like some of the previous commands, we can delete multiple things at once by using the following format:

rm [file1] [file2] [etc]
24.png
We delete “afile.txt” and “anotherone.txt”

In the example above, we delete “afile.txt” from the current directory and subsequently delete “anotherone.txt” from the previous or parent directory.

If we wanted to delete only certain files that end in specific extensions (i.e. .txt, .png, .exe, etc) we would use the asterisk or “*” symbol. This symbol is often referred to as a wildcard.

For example, if we were in a directory and we only wanted to delete .txt files, we would do the following:

rm *.txt
25.png
We delete various .txt files.

As you can see, we deleted all the files that end with the “.txt” extension. If we had other files such as .png, .gif, etc, those files would be unscathed by the rm command.

So by using the “*” symbol we effectively tell the terminal to disregard the name of the file and only look at the extension of the file.

Now let’s get into the danger zone.

Earlier I said that most if not all commands have something called options. These options are added right after the command like so:

[command] [options] [other paramters]

Well, the rm command has two options that I’m going to show you which are dangerous if used without precaution and quite lethal in combination.

rm -r

The first is the “-r” option. As you may recall, I said that the “-r” option means do it recursively, which is just another way of saying all or targeting everything.

If you do the following command:

rm -r [directory]

it will delete everything inside of a directory including the folder itself.

So if I have the following directory:

newfolder
├── folder1
│   └── text1.txt
├── folder2
│   └── text2.txt
└── folder3
    └── text3.txt

and then I input the following command:

rm -r newfolder

It will delete everything within the “newfolder” directory as well as the folder itself.

26.png
We delete all of the contents of the “newfolder” directory including the folder itself.

As a side note, the ‘tree’ command isn’t available by default on Mac, you have to download and install it seperately.

Now we move onto the other option, “-f.”

rm -f
rm -f [file/directory]

Sometimes, when you use the rm command, you may get a prompt. This prompt may just be something like “Are you sure you want to delete the following file or directory?”

By using this option, you avoid having the prompt show up in the first place.

Essentially, this just tells the terminal, “Delete the following file/directory and don’t give me a prompt.”

Now we move onto the most lethal combination, “-rf.”

rm -rf
rm -rf [directory]

When you combine both the “r” and the “f” options, you’re telling the terminal “Delete all of the contents of the directory and don’t show me a prompt, capeesh.”

As you can probably guess, this is quite dangerous.

No need to fret though, as long as you’re cautious and don’t use this command on let’s say, you’re root directory, you should—for the most part—be fine.

It's also important to note that on Linux if you run this command on your root directory, it'll remove it without a moment's hesitation.

You won't get a prompt or a warning saying "Hey my dude, are you sure you want to delete your root directory?" No! Instead, Linux will just be like "Okay sure, say no more" and will go ahead and delete everything inside your root directory essentially destroying your system.

Alright, so now that we know what the “r” and “f” options do, let’s run through an example.

Here I have a directory which looks something like this:

anotherfolder
└── myfolder
├── folder1
│   └── file1.txt
├── folder2
│   └── file2.txt
├── folder3
│   └── file3.txt
└── folder4
    └── file4.txt

Now if I run the following command (assuming I’m already at the “anotherfolder” location):

rm -rf myfolder

It should delete all the contents inside the “myfolder” directory including the folder itself and I shouldn’t see any prompts.

All right, let’s give it a shot.

27.png
We remove all the contents of “myfolder” including the folder itself.

Sure enough, it worked.

Finally, I want to talk about one more useful command called man or manual.

man - manual
man [command name]

This command lets you look up what other commands do. So let's say for some reason you remember a command but forget what it does, you can use man to look up its functionality.

For example, if I forgot what mv did, I would do the following:

man mv
man mv.png
The functionality for the mv command.

You can use the arrow ↑ or arrow↓ keys on your keyboard to read through its functionality and once you're done you can press "Q" to quit and return back to your previous page.

The man commands also gives you a list of options associated with the command you looked up like so:

man mv options.png
The options associated with the mv command.

Now let’s recap what we learned.

Recap

It’s useful to think of directories as a hierarchical tree with the topmost directory being the root directory.

The “.” means current directory while “..” means previous or parent directory.

The actual program you are interacting with is called the shell.

You can use tab to autocomplete commands, paths, or file names.

You can also use the arrow ↑ and arrow↓ keys to cycle through previous commands as well as the arrow ← or arrow → to move the cursor.

We also took a look at the following commands:

  • pwd prints the current working directory
  • ls lists all the contents of the current directory
  • cd [directory name] changes directory
  • clear clears the terminal screen
  • mv [source] [destination] moves files or folders from one place to another and can rename files or folders
  • cp [source] [destination] copies files or folders from one place to another
  • open [file/directory] opens the file or folder with the associated program
    • "xdg-open" is the equivalent on Linux.
  • mkdir [directory name] makes a new empty directory
  • touch [file name] creates a new empty file with the name of your choice and can update a file's timestamps
  • rmdir [empty directory] removes an empty directory
  • rm [file name] removes a file
  • rm -rf [directory name] removes the folder and its contents without showing any prompts
  • man [command name] brings up the manual for the given command

And this is only scratching the surface of the terminal.

There are many more useful commands but these are just the basics to get you up and running.

Where to Go From Here?

If you want to learn more about the commands we went over, I highly suggest you look up every command we talked about using man, including the man command itself.

In addition here are some other commands that I didn't go over but are just as useful:

  • cat concatenates and prints files to the terminal
  • less displays contents of a file
  • grep searches files for a certain word or regular expression
  • ls -l lists files in long format
  • kill can terminate a signal or process
  • chmod allows you to change or modify access permissions of a file or folder
  • sudo a prefix that allows you to run commands as a superuser with root privileges
  • mkdir you can create multiple directories within the same path
  • w tells you who's logged in and what they're doing

Thank you for reading and I hope this helps!