The Unix filesystem


Marie-Hélène Burle

Bash allows to give instructions to a Unix operating system. The first thing we need to know is how storage is organized on such as system.


The Unix filesystem is a rooted tree of directories. The root is denoted by /.

Several directories exist under the root. Here are a few:

  • /bin     This is where binaries are stored.
  • /boot    There, you can find the files necessary for booting the system.
  • /home    This directory contains all the users home directories.

These directories in turn can contain other directories. /home for instance contains the directories:

  • /home/user001
  • /home/user002
  • /home/user003

The home directory of each user contain in turns many files and directories.

Absolute and relative paths

Absolute paths give the full path from the root (e.g. /bin, /home/user009/file).

Relative paths give the path relative to the working directory (e.g. ../dir/file, dir)

Your turn:

Is ~ an absolute or relative path?

Creating files and directories

Files can be created with a text editor:

nano newfile.txt

The file actually gets created when you save it from within the text editor.

or with the command touch:

touch newfile.txt

This creates an empty file.

touch can create multiple files at once:

touch file1 file2 file3

New directories can be created with mkdir. This command can also accept multiple arguments to create multiple directories at once:

mkdir dir1 dir2


Files can be deleted with rm.

Directories can be deleted with rm -r (recursive) or, if they are empty, with rmdir.

Be careful that these commands are irreversible.

Copying, moving, and renaming

Copying is done with the cp command. Moving and renaming with the mv command.

Your turn:

Why is there only one command to move and rename?