UNIX® Shells by Example Fourth Edition

Chapter 12. Programming the Korn Shell

Introduction

When commands are executed from within a file, instead of from the command line, the file is called a shell script and the shell is running noninteractively. Writing Korn shell scripts requires a few steps, as outlined in the following section.

The Steps in Creating a Shell Script

A shell script is normally written in an editor and consists of commands interspersed with comments. Comments are preceded by a pound sign (#).

The First Line

At the top left corner, the line preceded by #! (often called shbang) indicates the program that will be executing the lines in the script. In Korn shell scripts, this ...