Terminal Basics

The terminal is a text interface for your system. When you type and enter a command, the shell executes them and prints the result. The program interpreting your commands is called a shell. On most Linux systems, thats bash or zsh. On MacOS, as of October 2019, the shell used is zsh.

When you open a terminal, you’re inside:

• A user session
• A current working directory
• A running shell process Understanding those three things prevents most mistakes beginners make.

One important note is that most commands, especially filesystem related ones, are non-verbose by default. They do not print any output if they succeed. You will have to check manually. (e.g. through ls)

The prompt

You’ll see something like this:

user@machine:~$

This tells you:

• user - your username, which you can alternatively check with the whoami command.
• machine - your hostname, which you can check with hostname.
• ~ - your current working directory (CWD), which you can check with pwd. Note that ~ is a shorthand for /home/user.
• $ - normal user. If you’re in root, you would see #.

Some Linux distros may show more or less information in different formats, though it will almost always show the username, machine, CWD and privilege mode.

Where you are

The directory you’re inside of is called the “current working directory”. Using pwd, which essentially means “Print Working Directory”.

The shell always runs code relative to your current location unless you specify an absolute path.

user@machine:~$ pwd
/home/user

Listing files

To list the files in your current working directory, or a specified path, you use the ls command.

user@machine:/$ ls
bin   dev     etc   init  lib64       media  opt   root  sbin  sys  usr  wslAbmapn  wslKpbMpn  wslollFpn
boot  Docker  home  lib   lost+found  mnt    proc  run   srv   tmp  var  wslDBakmn  wslLhbmim

However you can also add the -l flag to have a more detailed listing of the files, including permissions, owner, and size. You can also add the -a flag to include hidden files.

user@machine:/$ ls -la
total 2772
drwxr-xr-x  24 root root    4096 Mar  2 13:21 .
drwxr-xr-x  24 root root    4096 Mar  2 13:21 ..
lrwxrwxrwx   1 root root       7 Aug 18  2025 bin -> usr/bin
drwxr-xr-x   2 root root    4096 Aug 18  2025 boot
drwxr-xr-x  13 root root    3700 Mar  2 13:21 dev
drwxr-xr-x   3 root root    4096 Dec 19 17:02 Docker
drwxr-xr-x  89 root root    4096 Mar  2 13:21 etc
drwxr-xr-x   3 root root    4096 Nov 23 12:01 home
-rwxrwxrwx   1 root root 2735264 Aug  7  2025 init
lrwxrwxrwx   1 root root       7 Aug 18  2025 lib -> usr/lib
lrwxrwxrwx   1 root root       9 Aug 18  2025 lib64 -> usr/lib64
drwx------   2 root root   16384 Nov 23 12:01 lost+found
drwxr-xr-x   2 root root    4096 Sep 15 22:09 media
drwxr-xr-x   5 root root    4096 Nov 23 12:01 mnt
drwxr-xr-x   2 root root    4096 Sep 15 22:09 opt
dr-xr-xr-x 247 root root       0 Mar  2 13:21 proc
drwx------   4 root root    4096 Dec 19 17:02 root
drwxr-xr-x  16 root root     440 Mar  2 13:21 run
lrwxrwxrwx   1 root root       8 Aug 18  2025 sbin -> usr/sbin
drwxr-xr-x   2 root root    4096 Sep 15 22:09 srv
dr-xr-xr-x  13 root root       0 Mar  2 13:21 sys
drwxrwxrwt  70 root root   12288 Mar  2 13:27 tmp
drwxr-xr-x  16 root root    4096 Nov 23 12:41 usr
drwxr-xr-x  11 root root    4096 Nov 23 13:30 var
drwx------   2 root root    4096 Dec 20 15:15 wslAbmapn
drwx------   2 root root    4096 Dec 20 15:15 wslDBakmn
drwx------   2 root root    4096 Dec 20 15:15 wslKpbMpn
drwx------   2 root root    4096 Dec 20 15:15 wslLhbmim
drwx------   2 root root    4096 Dec 20 15:15 wslollFpn

Hidden files are typically configuration files.

Changing directories

To move to a directory, you use cd.

user@machine:/$ cs home
user@machine:/home$

. refers to the current directory, and .. refers to the parent directory.

For instance, if you’re in ~ and wish to go back one-level.

user@machine:~$ cd ..
user@machine:/home$

Note that since ~ is a shorthand for /home/user, when you go to its parent directory, it says /home.

Absolute vs Relative paths

Absolute paths are paths that start from the root (/). For instance, /home/user/Documents is an absolute path. Relative paths are paths relative to the CWD. For instance, If you’re in ~, the same directory would instead be Documents.

Note that file paths in UNIX are case-sensitive. Documents is not the same as documents.

File operations

Creating an empty file is done through touch.

user@machine:~$ touch example.txt

user@machine:~$ ls
example.txt

To create a directory, similar to windows, you can use mkdir.

user@machine:~$ mkdir example

user@machine:~$ ls
example

To remove a folder, you can use rmdir. Do note that the folder must be empty.

user@machine:~$ rmdir example

user@machine:~$ ls

To remove a file, you can use rm. You should be careful with rm as it does not delete to a trashbin.

user@machine:~$ rm example.txt

user@machine:~$ ls

Note that the rm command can be used to delete folders too if you utilize the -r(recursive) flag. You can also use the -f flag to force deletion.

user@machine:~$ ls example
example.txt  file1.txt  file2.txt  folder1  folder2
user@machine:~$ rm -rf example

user@machine:~$ ls

To print the file contents, you can use the cat command.

user@machine:~$ cat example.txt
lorem ipsum dolor sit amet

For longer files, use less.

user@machine:~$ less example.txt

Once you use less, your terminal will clear and the contents of the file will be shown. You can press q to exit this screen, or press j to scroll down and k to scroll up. You can also scroll with arrow keys.

To modify a file’s contents, you can use nano or vim(or the more modern, nvim). For our purposes, we will be using nano as it is the easiest to learn.

user@machine:~$ nano example.txt

You do not need to have a file location in the command, having one simply writes to that file location. Once you enter the command, your screen will be cleared and replaced with the nano TUI (Text-based User Interface). You can edit your content as you usually would, however a few keybinds like copy and pasting and what not are remapped. You can view the keybinds at the bottom section.

Once you want to save your file in nano, press Ctrl + O and enter to confirm the file path. Finally, press Ctrl + K and enter to exit the TUI.

For now, you don’t require vim as it is a more advanced text editor. If you do enter it by accident, type :q to exit. You may need to press escape if it says “INSERT” at the bottom of the screen.

Command history

Press the up arrow to scroll through previous commands. You can also search history via doing Ctrl + R and typing part of a command.

This is faster than retyping long commands.

Autocomplete

Press Tab while typing a command or filename and the shell will attempt to auto-complete it. This can reduce typos and speeds up workflows.

Stopping a running command

If a command runs for too long, use Ctrl + C. This is also known as a SIGINT (Signal Interupt) to the running process. You’ll use this frequently when testing scripts or if something were to hang.