/ What is Sudo?

Basic Linux console commands

Just like navigating a desktop, it is important to be able to navigate a console.

This post is part of the "what is sudo?" series, which aims to help understand Linux and text consoles.

Dealing with files

Every folder in a system except the root folder is inside another folder. This other folder is the parent folder. The root folder, or top-most folder, is the folder that contains everything in your system.

The root folder is: /.

Some users in your system have associated "home" folders. You can think of this folder as where a user would normally put their own "Documents", "Photos", etc.

Whenever you use a system, you must be logged in as a specific user. Let's find out what your current user is.

Open a console, and type the following command:

whoami

This will tell you the name of the user you are currently logged in as.

Next, lets navigate to your user's "home" folder:

cd ~

The cd command performs a change directory command. The ~ folder is the current user's "home" folder.

Creating files and folders

To create a folder, we use the mkdir command.
To create an empty file, we use the touch command.

# This creates a folder 'documents' inside your home folder.
mkdir ~/documents

# This creates an empty file 'hello.txt' in the documents folder.
touch ~/documents/hello.txt

If we want to create a folder inside another folder, neither of which exist:

mkdir -p ~/documents/work/journal

This creates a folder called 'work', and then a folder called 'journal' inside it. If we omit the -p, then it gives an error because it attempts to create the 'journal' folder inside a folder that doesn’t yet exist ('work').

Deleting files and folders

Finally, lets look at deleting. We delete using the rm command.

# This deletes the file 'hello.txt'
rm ~/documents/hello.txt
# This deletes the folder 'work', including everything it contains
rm -rf ~/documents/work

The -rf argument is required in order to delete folders. This is because we want to delete everything inside the folder, as well as the folder. The r stands for "recursive", which tells the rm command to go into each sub-folder and delete everything in it. The f argument attempts to delete files even if they are not owned by the currently logged in user.

Review

  • whoami shows the currently logged in user.
  • cd [args] changes directory to another directory.
  • mkdir [-p] [args] creates a directory.
  • touch [args] creates an empty file.
  • rm [-rf] [args] removes a file or directory.