Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By : Richard Blum, Christine Bresnahan
Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By: Richard Blum, Christine Bresnahan

Overview of this book

The Linux command line enables you to type specific shell commands directly into the system to manipulate files and query system resources. Command line statements can be combined into short programs called shell scripts, a practice increasing in popularity due to its usefulness in automation. Linux is a robust system with tremendous potential, and Linux Command Line and Shell Scripting Bible opens the door to new possibilities. Linux Command Line and Shell Scripting Bible is your essential Linux guide. It contains new functional examples that are fully updated to align with the latest Linux features. Beginning with command line fundamentals, the book moves into shell scripting and shows you the practical application of commands in automating frequently performed functions. This book is a complete guide providing detailed instruction and expert advice working within this aspect of Linux. Whether used as a tutorial or as a quick reference, this book contains information that every Linux user should know.
Table of Contents (34 chapters)
2
Part I: The Linux Command Line
13
Part II: Shell Scripting Basics
20
Part III: Advanced Shell Scripting
28
Part IV: Creating Practical Scripts
32
End User License Agreement

Controlling the Job

Earlier in this chapter, you saw how to use the Ctrl+C key combination to stop a job running in the shell. After you stop a job, the Linux system lets you either kill or restart it. You can kill the process by using the kill command. Restarting a stopped process requires that you send it a SIGCONT signal.

The function of starting, stopping, killing, and resuming jobs is called job control. With job control, you have full control over how processes run in your shell environment. This section describes the commands used to view and control jobs running in your shell.

Viewing jobs

The key command for job control is the jobs command. The jobs command allows you to view the current jobs being handled by the shell:

$ cat test10.sh
#!/bin/bash
# Test job control
#
echo "Script Process ID: $$"
#
count=1
while [ $count -le 10 ]
do
   echo "Loop #$count"
   sleep 10
   count=$[ $count + 1 ]
done
#
echo "End of script..."
#
$ 

The script uses the...