Unix shells provide a method of running more that one command, or shell script, at a time by placing the command into the background with an “&”. A command placed into the background will continue to run and get CPU cycles while allowing you to run new commands without having to open a new terminal. This is especially useful when executing long-running commands, when running tasks that can benefit from running in parallel, when physically connected to the system terminal, or when opening a new terminal just isn’t convenient.

Once a command has been placed into the background, shells provide a method for controlling and monitoring the background commands using something known as job control. It’s the use of job control, specifically from within a Korn shell script, which is the topic of this article.

By Rainer Raab at UNIX Review.

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