The Linux File System Tree

One big tree

On Windows you have drives like C:\ and D:\. Linux has no drive letters. Instead, every file and folder lives in a single tree that starts at the root directory, written as a single slash: /.

Here is a small part of the tree on our lab machine:

/
├── bin        programs (commands) everyone can run
├── etc        system settings
├── home       the users' home folders
│   └── student    your home folder
├── root       the administrator's home folder
├── tmp        temporary files
├── usr        installed programs and their files
└── var        data that changes: logs, caches, mail

Folders are usually called directories on Linux. The two words mean the same thing.

Think of it like this: Think of the file system as a tree turned upside down. / is the trunk at the top. Each directory is a branch, and files are the leaves at the ends of the branches.

Paths

A path is the address of a file: the list of directories you go through to reach it, separated by /. Your home folder's path is:

/home/student

Read it from left to right: start at the root /, go into home, then into student. A file called notes.txt inside it has the path /home/student/notes.txt.

Your home directory

Every user has a home directory for their own files, normally /home/<username>. When you open a terminal, you start there. The shell uses the short name ~ (tilde) for it, which is why the prompt shows ~.

Names are case-sensitive

Notes.txt, notes.txt and NOTES.TXT are three different files on Linux. And as you saw in module 1, files whose names start with a dot are hidden.

Tip: File names can contain spaces, but they make typing commands harder. Linux users prefer my_notes.txt or my-notes.txt to my notes.txt.

Remember: Everything starts at /. A path like /home/student/notes.txt is the address of a file. ~ is your home directory.