Further Reading

Linux System Administrator’s Guide
Admin Made Easy Guide
Shell Programming

The command interpreter, or Shell, under Linux also supports programming. Shell is a sort of interface between the user and the operating system. It parses the user commands and get the job done by making necessary system calls and by running appropriate programs. Shell also offers facilities like variable declarations and control flow constructs so that you can program using that. A working knowledge of shell scripting is essential to everyone wishing to become reasonably adept at system administration, even if they do not anticipate ever having to actually write a script. Consider that as a Linux machine boots up, it executes the shell scripts in /etc/rc.d to restore the system configuration and set up services. A detailed understanding of these startup scripts is important for analyzing the behavior of a system, and possibly modifying it

.If you want to learn shell programming refer to the.

Advanced Bash Scripting Guide