For system, network and cloud administrators

What is a “shell”?

The Bourne Shell: /bin/sh

The shell is one of the most important parts of a Unix system and that’s why developers and admins around the world rely so much on it. It’s basically a program inside which the user can run commands and create shell scripts. Unix programmers used the shell as a programming environment too. In fact, a lot of the important parts of the Unix system itself are … shell scripts.

The shell is called the Bourne shell (/bin/sh) because of the standard shell that Bell Labs developed for early Unix versions. From this Bourne shell, most of the current and modern shells derive from.

A Linux shell is called bash

Linux itself uses an improved, enhanced for-the-user’s-needs, Bourne shell “or the ‘Bourne-again’ shell” (p. 37, How Linux works – what every superuser should know, Brian Ward). Most Linux distributions out there use the bash shell as the default shell. At its core, the bash shell itself is just a link from /bin/sh.

A shell window is usually called a terminal

When the user launches a new shell window, that’s often referred to as a terminal window. The terminal can be seen in a couple of different forms, depending on the operating system. For example:

  • when opening an Ubuntu terminal, a prompt should appear that ends with a dollar sign ($); the full prompt should look more like username@host:path$;
  • when opening a Fedora terminal, the terminal’s prompt should be something like [username@host path]$.

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