What is the Shell

The Shell is the default user interface to Linux system. The Graphical User Interface (GUI) is called graphical shell, however if not specific, people are typically talking about the Command Line Interface (CLI).

The Shell is a program that accepts and executes your commands.

Command Line vs. a GUI

• The command line is more powerful. For example, you have many files and you need to perform the same operation (E.g. rename) on them, you can often do this easily at the shell.
• There will always be a command line.
• Linux Server distributions do not include GUI. You are typically going to connect a Linux Server via SSH. This will give you access to the command line interface.
• Linux Desktop distributions have GUI and Command Line Interface

The Prompt (Shell Prompt)

When the shell is started, it displays a prompt or a shell prompt. The prompt simply just sits there and wait for you to enter a command to execute.

[robin@myserver ~]$

A shell prompt typically gives you some sort of useful information. In above example, you will see a user name robin and the server you connected to myserver. You are in your home directory, shown as tilde ( ~ ) sign. At the end of the prompt you will see a dollar sign, this indicate that you are using a normal user. For a superuser, it shows dash ( # ) sign.

[robin@myserver ~]#

The superuser user on a Linux system is also called root.

Root account

In the Linux directory, we have mentioned about the root of the file system or /. This is an accout called root, a superuser.

• Root is a superuser, similar to an administrator account on a Windows system.
• Normal accounts can only do a subset of the things root can do.
• Root access is typically restricted to system administrators.
• Root access may be required to install, start or stop an application.
• Day to day activities will be performed using normal account.