Chapter 7. Conquering the bash Shell
The real power of
Linux lies in the shell. So, if you aspire to master Linux, you must
conquer the shell. Once you’ve done so, you’ll have the
ability to direct your system to do almost anything. This chapter
describes the powerful bash
shell. The chapter
also briefly explains shell variables, shell scripts, and shell
aliases, preparing you for an in-depth, continuing study of Linux and
its shell.
Issuing Shell Commands
The component of Linux that interprets
and executes commands is called the shell.
Usually, you’ll access the shell via a terminal window, as
explained in Chapter 5 and Chapter 6. However, the section “Using Virtual
Consoles” later in this chapter explains how to use a virtual
console. Linux supports a variety of different shells, but the most
popular is the bash
shell. The Linux
bash
shell presents the user with a
Command Line Interface
(CLI). CLIs are familiar
to Windows users who have worked in the MS-DOS window, and indeed the
Windows MS-DOS Prompt window is a kind of command-line shell. The
Linux bash
shell works much like the MS-DOS
Prompt window; you type text commands and the system responds by
displaying text replies. As your first Linux command, type w and press Enter. Your contents of the terminal window
should look something like this:
[bill@home bill]$ w
11:12am up 6 min, 1 user, load average: 0.00, 0.08, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
bill tty1 11:11am 0.00s 0.20s 0.11s -bash
The w command ...
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