Bash

Bash is a command-line shell commonly used on Linux systems. It allows you to interact with your computer by entering commands into a terminal.

On Raspberry Pi OS, Bash is available by default.

Getting Started

When you open a terminal, Bash displays a command prompt indicating that it is ready for you to enter a command.

The appearance of the prompt varies between systems and can be customized. For example, a prompt might display information such as your username, hostname, or current directory. This could look like:

username@hostname:~ $

Type a command and press Enter to run it.

Paths

A path describes the location of a file or directory.

An absolute path starts from the root directory /:

/home/username/Documents

A relative path starts from your current directory:

Documents/example.txt

The following have special meanings:

Path	Meaning
.	Current directory
..	Parent directory (one directory above your current directory)
~	Your home directory
/	Root directory

Directories (Folders)

Current Directory

Your current directory is the directory you are currently working in.

To see your current directory:

pwd

Listing Directory Contents

To see the files and directories inside it:

ls

To include hidden files:

ls -a

Moving to Different Directories

Use cd to move to a different directory:

cd directory

For example:

cd Documents

Creating Directories

Create a directory with mkdir:

mkdir example

Removing Directories

Remove an empty directory:

rmdir example

Files

Viewing a File

Display the contents of a text file:

cat example.txt

For longer files, you can use:

less example.txt

Use the arrow keys to move through the file and press q to quit.

Editing a File

There are multiple text editors available in the terminal. One example is Vim. You can open a text file in Vim with:

vim example.txt

See the Vim reference for the commands needed to edit, save, and quit.

Copying and Moving

Copy a file:

cp source destination

For example:

cp example.txt backup.txt

Move a file:

mv example.txt Documents/

mv can also be used to rename a file:

mv example.txt renamed.txt

Removing Files

Remove a file:

rm example.txt

Caution

Files removed with rm are not moved to a trash or recycle bin. Make sure you are removing the correct file before running the command.

Running Commands

Running Commands as Administrator

Some system changes require administrator privileges. Use sudo before a command to run it with elevated privileges:

sudo command

For example:

sudo apt update

You may be asked for your password.

Caution

Commands run with sudo have elevated privileges and can make system-wide changes. Make sure you understand a command before running it with sudo.

Stopping a Command

To interrupt a command that is currently running:

Ctrl+C

This is useful when a command is hanging or when you need to stop a running program.

Making Your Life Easier

Tab Completion

Press Tab while typing to automatically complete commands, file names, and directory names when possible.

For example, if the current directory contains a directory named Documents, you could type:

cd Doc

Then press Tab to complete it:

cd Documents/

If there is more than one possible match, press Tab again to display the available options.

Command History

Use the Up and Down arrow keys to move through commands you have previously entered.

To display your command history:

history

This displays previously entered commands along with their history numbers.

TL;DR: The Bare Minimum

Command	Action
pwd	Show where you are
ls	Show what’s here
cd directory	Change directory
mkdir name	Create a directory
cat file	Display a file
vim file	Edit a file using Vim
rm file	Remove a file
sudo command	Run a command with elevated privileges
Ctrl+C	Stop a running command