Command Line Basics

There are several different shells on Linux, these are just a few:

• Bourne-again shell (Bash)
• C shell (csh or tcsh, the enhanced csh)
• Korn shell (ksh)
• Z shell (zsh)

With the most common one being Bash.

When using an interactive shell, the user inputs commands at a so-called prompt. For each Linux distro, the default prompt may look a little different, but it usually follows this structure:

where:

• username is the name of the user that runs the shell.
• hostname is the name of the host on which the shell runs. You can change it or show the current host name with hostname.
• current_directory is the directory that the shell is currently in. A ~ means that the shell is in the current user's home directory.
• shell type
  • $ indicates the shell is run by a regular user.
  • # indicates the shell is run by the superuser root.

Here are some examples of the default prompt on different distros:

$ Regular user Ubuntu or Debian GNU/Linux

carol@mycomputer: ~$

# Super user Ubuntu or Debian GNU/Linux

root@mycomputer: ~#

$ Regular user Red Hat or CentOS

[carol@mycomputer ~] $

# Super user Red Hat or CentOS

[root@mycomputer ~] #