Directories & files in Linux

Linux has a very specific file structure, with certain folders containing certain information. But what are these folders, and how do you traverse them in the command line?

Location	Purpose	Aliases
/	The root directory in Linux, where all folders are stored. Think of this as the equivalent of the My Computer folder on Windows	N/A
/home/USERNAME	Where all of your personal files are stored. This usually contains Desktop, Downloads, Documentsetc	~/
.	A representation of the current directory. For example, if you have a document called README.md in your current folder, it could be called ./README.md	N/A
..	Similar to ., but representing the upper directory. For example, if you wanted to go to the upper directory, you could use cd ..	N/A

LS

ls is the command often taught first to Linux beginners, as it it easy to use and provides information for use in other commands. ls lists the contents of a directory, showing all files & folders inside. Here are some examples of regular ls usage:

Command	Usage
ls	Lists the contents of the current directory
ls -a	Lists the contents of the current directory, including files beginning with .
ls -l	Lists the contents of the current directory, with additional information such as date modified and user permissions
ls DIR	Lists the contents of the directory DIR
ls ..	Lists the contents of the parent directory

Some common ls flags are:

Flag	Shorthand	Description
--all	-a	Do not ignore entries starting with . (dotfiles are files and folders that are intentionally hidden, usually to reduce clutter)
-l	-l	Display data in a long format
-S	-S	Sort by size, largest first

Remember that you can stack flags! Try looking into some of the options for each command, and see what outputs you can produce.

CD

One of the commands you will use most often in Linux is cd. CD stands for Change Directory, which helps the user to move their current directory. Here are some examples of regular cd usage:

Command	Usage
cd	Moves to the home directory
cd ..	Moves to the parent directory
cd -	Moves to the last directory. For example, you can use cd / to enter the root directory and cd - to return to your previous directory
cd DIR	Moves to the directory DIR

MKDIR

To create a folder in Linux, you can use the command mkdir. This command is relatively simple, with only basic application:

Command	Usage
mkdir DIR	Creates an empty directory called DIR
mkdir ../DIR	Creates an empty directory called DIR in the parent directory

TOUCH

Similar to mkdir, touch is a command that creates an empty file at the specified location. Again, this command only has basic applications:

Command	Usage
touch test.txt	Creates an empty file called test.txt
touch ../test.txt	Creates an empty file called test.txt in the parent directory

Keep in mind that most of these commands take a path as input, and therefore can be more than just one part. For example, you can use cd ../../.. to travel many directories at once, or mkdir ~/test to create an empty directory in your home. Try playing around with more complicated directory usage now, as it will assist you later on with more complex folder structures!