BSD Unix® Toolbox: 1000+ Commands for FreeBSD®, OpenBSD, and NetBSD®

Chapter 3. Using the Shell

IN THIS CHAPTER

Accessing the shell

Using the shell

Acquiring super-user powers

Using environmental variables

Creating simple shell scripts

The use of a shell command interpreter (usually just called a shell) dates back to the early days of the first UNIX systems. Besides their obvious use of running commands, shells have many built-in features such as environment variables, aliases, and a variety of functions for programming.

There are several different shells to choose from on BSD systems. By default, the root user is assigned to use the C shell (csh) and a regular user is assigned the Bourne shell (sh). With Linux systems, most users use what is called the Bourne Again Shell (bash). There are other shells available as well (such as zsh, ksh, or tcsh).

This chapter offers information that will help you use BSD shells, in general, and the bash shell, in particular.

Terminal Windows and Shell Access

The most common way to access a shell from a BSD graphical interface is using a Terminal window. From a graphical interface, you can often access virtual terminals to get to a shell. With no graphical interface, and a text-based login, you are typically dropped directly to a shell after login.

Using Terminal Windows

To open a Terminal window from GNOME, select Accessories

Figure 3-1. Type shell commands into a gnome-terminal window.

Commands shown in Figure 3-1 illustrate ...