Training Missions

Missions: Using command line shell

Using command line shell

What is "the shell"?

In simple words, the shell is a program that takes your commands from the keyboard and gives them to the operating system to perform. In the old days, it was the only user interface available on a computer. Nowadays, we have graphical user interfaces (GUIs) in addition to command line interfaces (CLIs) such as the shell.

On most Linux systems a program called bash acts as the shell program. There are several additional shell programs available on a typical Linux system. These include: ksh, tcsh and zsh.

How to start the shell?

Most window managers have a way to launch programs from a menu. Look through the list of programs to see if anything looks like a terminal emulator program. In KDE, you can find "konsole" and "terminal" on the Utilities menu. In Gnome, you can find "color xterm," "regular xterm," and "gnome-terminal" on the Utilities menu. You can start up as many of these as you want and play with them. While there are a number of different terminal emulators, they all do the same thing. They give you access to a shell session. You may develop a preference for one, depending on different features each one provides. Ubuntu users may see here for a detailed description about how to start a terminal.

For the rest of the mission we recommend you to start your shell and play with the commands as we present them before you.

What you'll learn

After completing this mission, you will have a basic understanding of the shell and some basic commands, which will help you in understanding other missions.

Getting started

This mission will provide you information about few of the most frequently used commands in the shell. This mission also consist of a "Challenge", which will be a question at the end of the tutorial of every command.