Goals for this Hour

In this hour, you learn

• About job control in the shell: stopping jobs

• How to put jobs in background and bring them back to the foreground

• How to find out what tasks are running by using jobs and ps

• How to terminate errant processes by using kill

Throughout this book, I've indicated that my focus is on the most important and valuable flags and options for the commands covered. That's all well and good, but how do you find out about the alternatives that might actually work better for your use?

This hour presents an explanation of a UNIX philosophical puzzle: What is a running program? To learn the answer, you are introduced to ps and jobs, for controlling processes; fg and bg, to move your own processes back and forth between the foreground and background; and the quasi-omnipotent kill command, for stopping programs in their proverbial tracks.