Scripts or interpreted programs are often used to automate various tasks in Linux. This chapter focused on writing scripts in Bash-the Bourne Again shell-as well as in the scripting language Perl.
By reading this chapter, you learned the following:
A shell script is nothing more than a sequence of Linux commands in a file. Typically, you have to place a special line at the beginning of the script file and make it executable. Then you can run the script by typing its name at the shell prompt.
When your Red Hat Linux system boots, shell scripts stored in various subdirectories in the /etc directory (for example, /etc/init.d) perform many initialization tasks.
There are many built-in shell commands you can use in shell scripts. You already know some of the built-in commands, such as cd and pwd, but this chapter describes many more built-in shell commands.
Perl is a popular scripting language that appears on this book's companion CD-ROMs. You can use Perl to write powerful scripts on your Red Hat Linux system.
Perl contains features comparable to those of other programming languages, such as C. A powerful feature of Perl is its capability to use regular expressions and to search files for occurrences of a search pattern.
Perl 5, the latest version of Perl (and the one that comes with Red Hat Linux), includes a number of helpful features. A key feature is the Perl module, a package of subroutines that follows certain guidelines. Modules make it possible to implement objects in Perl.
You can download the latest version of Perl (as well as Perl documentation) from the Comprehensive Perl Archive Network (CPAN) at http://www.perl.com/CPAN/.