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<!-- %MENU% All about process groups and sessions -->
<h2 class="chapter">27 Job Control</h2>

<p><a name="index-process-groups-3196"></a><a name="index-job-control-3197"></a><a name="index-job-3198"></a><a name="index-session-3199"></a><dfn>Job control</dfn> refers to the protocol for allowing a user to move
between multiple <dfn>process groups</dfn> (or <dfn>jobs</dfn>) within a single
<dfn>login session</dfn>.  The job control facilities are set up so that
appropriate behavior for most programs happens automatically and they
need not do anything special about job control.  So you can probably
ignore the material in this chapter unless you are writing a shell or
login program.

   <p>You need to be familiar with concepts relating to process creation
(see <a href="Process-Creation-Concepts.html#Process-Creation-Concepts">Process Creation Concepts</a>) and signal handling (see <a href="Signal-Handling.html#Signal-Handling">Signal Handling</a>) in order to understand this material presented in this
chapter.

<ul class="menu">
<li><a accesskey="1" href="Concepts-of-Job-Control.html#Concepts-of-Job-Control">Concepts of Job Control</a>:      Jobs can be controlled by a shell. 
<li><a accesskey="2" href="Job-Control-is-Optional.html#Job-Control-is-Optional">Job Control is Optional</a>:      Not all POSIX systems support job control. 
<li><a accesskey="3" href="Controlling-Terminal.html#Controlling-Terminal">Controlling Terminal</a>:         How a process gets its controlling terminal. 
<li><a accesskey="4" href="Access-to-the-Terminal.html#Access-to-the-Terminal">Access to the Terminal</a>:       How processes share the controlling terminal. 
<li><a accesskey="5" href="Orphaned-Process-Groups.html#Orphaned-Process-Groups">Orphaned Process Groups</a>:      Jobs left after the user logs out. 
<li><a accesskey="6" href="Implementing-a-Shell.html#Implementing-a-Shell">Implementing a Shell</a>:         What a shell must do to implement job control. 
<li><a accesskey="7" href="Functions-for-Job-Control.html#Functions-for-Job-Control">Functions for Job Control</a>:    Functions to control process groups. 
</ul>

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