Section 6.1. Introduction

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6.1. Introduction

Bash is the shell of choice on Linux systems. It implements all the core facilities described in Chapter 5, "The Linux Shells," and is compatible with the original UNIX Bourne shell (so Bourne shell scripts run under Bash). Bash conforms to the POSIX standard for command shells (IEEE 1003.2). Bash also implements the best features from the original UNIX C shell.

On Linux systems, Bash is installed as /bin/bash, but /bin/sh is a pointer to /bin/bash, since any script expecting Bourne shell functionality will run properly under Bash.

The following features of Bash that are new or a bit different from what has been discussed in previous chapters include:

• variable manipulation

• command-line processing, aliases, and history

• arithmetic, conditional expressions, control structures

• directory stack

• job control

• shell functions