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

ls 

List current files and folders in directory

ls -al 

List everything

pwd 

Prints the current working directory

cd <directory> 

Move to a specified directory eg “cd .. ” will take you one level up

ifconfig 

Shows details on current network interfaces

touch <file> 

Create <file>

nano <file> 

Opens <file>in the nano text editor

vim <file> 

Opens <file>in the vim text editor

mkdir <dir> 

Creates the folder specified in <dir>

sudo <cmd> 

executes the command <cmd>with sudo privileges

raspi-config

Opens up the Raspberry Pi Configuration Tool. Must be run as administrator

man <command> 

Opens the manual for a particular command

ssh 

Creates an SSH session.

scp 

Secure copy.

An example output of running some commands in the shell

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