Shell Programming: Hands-On

What is this course about?

This course provides a comprehensive introduction to shell programming using the KornShell (ksh) and BASH shell (bash). A shell is a command-interpreting language used in UNIX/Linux. KornShell and Bash are the most powerful of the many available shells.

Of the other UNIX/Linux shells, KornShell and BASH are closely related. The Bourne shell (sh) represents a subset of the KornShell. The KornShell is POSIX- and SUS- compliant.

What is Shell programming used for?

Both KornShell and BASH are much more than simple command interpreters. They also serve as a scripting language, allowing you to write scripts to perform such tasks as customizing your working environment and automating repetitive functions. Shell scripts are heavily relied on by systems and application administrators, and power users who need to perform repetitive but important tasks on a regular basis, especially if the tasks need to be performed on a number of different machines.

Who will benefit from this course?

The course is for people who want to learn to become experts at writing scripts using KornShell or BASH. Shell scripting is most valuable for administrators, developers, support technicians and power users who could benefit from automating some online tasks.

How much UNIX background do I need to get the most out of this course?

This course assumes that you:

• Have experience with user-level UNIX commands such as ls, rm, cd, cp, and mv
• Know how to perform simple file editing with a basic text editor such as vi or emacs, or use a GUI based editor

Some familiarity with the X Window System and basic UNIX networking commands is desirable but not absolutely necessary. Course 428, UNIX^®: A Comprehensive Hands-On Introduction, or Course 143, Linux^®: A Comprehensive Hands-On Introduction, provides a more than adequate background for this course.

I'm working with XYZ flavor of UNIX. Is this course for me?

In a word, yes! This course runs on Linux using both David Korn's freely available, open source port of KornShell, and GNU BASH shell. The course content applies equally to Berkeley UNIXes (e.g., SunOS, Ultrix) and System V UNIXes, (e.g., HP/UX, AIX, Solaris, SCO), Apple Mac OS/X, and any distribution of Linux.

I don't work in a UNIX/Linux environment. Would this course be helpful to me?

Absolutely! One of the most interesting features of shell programming is its cross-platform compatibility. Shell scripts are used on a number of different operating systems, including Windows and OS/X. So if you need a robust, easy-to-learn scripting language for the Windows or OS/X environments, this course will be very useful to you.

How much time is spent on each topic?

How much time is spent on exercises?

Approximately 50% of the 3-day course is spent on exercises. You create a script on the course's first day. As the content builds, the exercises extend in length and complexity.

Because a shell is also an interactive command interpreter, most of the material is presented hands-on with continuous interactivity.

Why would I choose shell scripting over some of the other scripting languages out there?

The strength of shell programming is that it builds on skills you already have, so that you don't need to learn a new scripting language from scratch. Most UNIX/Linux users are already familiar with the shell, regular expressions and other command-line tools. You can add some muscle to your current skills by learning to package these commands into shell scripts, and automate the whole process. This lets you avoid the learning curve involved with mastering a new language.

I've heard people talk about "UNIX programming." Is shell programming sometimes referred to in this way?

No. It's true that shell scripting with the KornShell and BASH is programming, and it does usually take place within a UNIX or Linux environment. But the end result of this work is a script, not a stand-alone, compiled application.

When people refer to UNIX programming they're usually talking about writing applications in a standard language (e.g., C, C++ or Java) to run within a UNIX environment.

How does this course relate to other Learning Tree courses?

Learning Tree offers a broad variety of related courses. Those interested in building further skills working with the UNIX operating system might try:

• 396, UNIX® and Linux® Tools and Utilities: Hands-On provides a valuable overview of the many tools and utilities available to UNIX users
• 144, Linux® Administration and Support: Hands-On , provides the knowledge and skills to install and configure Linux servers for reliability, functionality and performance
• 433, UNIX® and Linux® Security: Hands-On outlines areas of vulnerability for UNIX systems, and explores strategies for improving UNIX/Linux system security

For information about working with Perl, consider:

• 431, Introduction to Perl Programming: Hands-On provides a comprehensive introduction to the syntax of Perl, an interpreted programming language