Unix Shell (Terminal)

Overview

Being able to use the Unix Shell and terminal commands is an invaluable skill, and a requirement for this course. Follow this software carpentry link for more learning resources.

Useful Commands

Command	Description
ls	List current files and folders in directory
ls -al	List details about everything
pwd	Print current (working) directory
cd <directory>	Move into the specified directory
cd ..	Move up one directory
ifconfig	Shows details on current network interfaces (requires package net-tools to be installed)
touch <file>	Creates a file. For example "touch.txt" will create a file in the directory you are in.
nano <file>	Opens the specified file in nano, a text editor
mkdir <directory>	Creates a directory
sudo <command>	Executes <command> with super user privilages
man <command>	Opens the user manual relating to the specified command

An example output of running some commands in the shell on a Raspberry Pi 3b+

Aliases

Sometimes you may want to run long or complex commands. In this scenario, it can be useful to create an alias. This allows you to rename a command (or chain of commands) to an easier to type or remember command. An alias is a sort of shortcut, and it can be temporary or permanent.

For example, the command vcgencmd measure_temp on a Raspberry Pi will return the core temperature. However, this can be a tricky command to remember. So, let's create an alias. For a temporary alias, you can just enter in alias temp="vcgencmd measure_temp" on the command line. This will allow you to type "temp" and get the temperature. However, this alias will expire when you end your session (log out). To create a permanent alias, the following is required.

1. Open .bash_profile: nano ~/.bash_profile
2. Add a line for the alias: alias temp="vcgencmd measure_temp"
3. Save and close the file
4. Reload .bash_profile: source ~/.bash_profile