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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>jobs</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="jobs"></a> <a name="tag_04_70"></a><!-- jobs --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_04_70_01"></a>NAME</h4><blockquote>jobs - display status of jobs in the current session</blockquote><h4><a name="tag_04_70_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><div class="box"><code><tt><sup>[<a href="javascript:open_code('UP')">UP</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> jobs</tt> <b>[</b><tt>-l| -p</tt><b>][</b><i>job_id</i><tt>...</tt><b>]</b><tt><img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div></blockquote><h4><a name="tag_04_70_03"></a>DESCRIPTION</h4><blockquote><p>The <i>jobs</i> utility shall display the status of jobs that were started in the current shell environment; see <a href="xcu_chap02.html#tag_02_12"><i>Shell Execution Environment</i></a> .</p><p>When <i>jobs</i> reports the termination status of a job, the shell shall remove its process ID from the list of those "knownin the current shell execution environment''; see <a href="xcu_chap02.html#tag_02_09_03_02"><i>Asynchronous Lists</i></a> .</p></blockquote><h4><a name="tag_04_70_04"></a>OPTIONS</h4><blockquote><p>The <i>jobs</i> utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap12.html#tag_12_02">Section 12.2, Utility Syntax Guidelines</a>.</p><p>The following options shall be supported:</p><dl compact><dt><b>-l</b></dt><dd>(The letter ell.) Provide more information about each job listed. This information shall include the job number, current job,process group ID, state, and the command that formed the job.</dd><dt><b>-p</b></dt><dd>Display only the process IDs for the process group leaders of the selected jobs.</dd></dl><p>By default, the <i>jobs</i> utility shall display the status of all stopped jobs, running background jobs and all jobs whosestatus has changed and have not been reported by the shell.</p></blockquote><h4><a name="tag_04_70_05"></a>OPERANDS</h4><blockquote><p>The following operand shall be supported:</p><dl compact><dt><i>job_id</i></dt><dd>Specifies the jobs for which the status is to be displayed. If no <i>job_id</i> is given, the status information for all jobsshall be displayed. The format of <i>job_id</i> is described in the Base Definitions volume of IEEE Std 1003.1-2001, <ahref="../basedefs/xbd_chap03.html#tag_03_203">Section 3.203, Job Control Job ID</a>.</dd></dl></blockquote><h4><a name="tag_04_70_06"></a>STDIN</h4><blockquote><p>Not used.</p></blockquote><h4><a name="tag_04_70_07"></a>INPUT FILES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_70_08"></a>ENVIRONMENT VARIABLES</h4><blockquote><p>The following environment variables shall affect the execution of <i>jobs</i>:</p><dl compact><dt><i>LANG</i></dt><dd>Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/xbd_chap08.html#tag_08_02">Section 8.2, Internationalization Variables</a> forthe precedence of internationalization variables used to determine the values of locale categories.)</dd><dt><i>LC_ALL</i></dt><dd>If set to a non-empty string value, override the values of all the other internationalization variables.</dd><dt><i>LC_CTYPE</i></dt><dd>Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte asopposed to multi-byte characters in arguments).</dd><dt><i>LC_MESSAGES</i></dt><dd>Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error andinformative messages written to standard output.</dd><dt><i>NLSPATH</i></dt><dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Determine the location of message catalogs for the processing of <i>LC_MESSAGES .</i> <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd></dl></blockquote><h4><a name="tag_04_70_09"></a>ASYNCHRONOUS EVENTS</h4><blockquote><p>Default.</p></blockquote><h4><a name="tag_04_70_10"></a>STDOUT</h4><blockquote><p>If the <b>-p</b> option is specified, the output shall consist of one line for each process ID:</p><pre><tt>"%d\n", <</tt><i>process ID</i><tt>></tt></pre><p>Otherwise, if the <b>-l</b> option is not specified, the output shall be a series of lines of the form:</p><pre><tt>"[%d] %c %s %s\n", <</tt><i>job-number</i><tt>>, <</tt><i>current</i><tt>>, <</tt><i>state</i><tt>>, <</tt><i>command</i><tt>></tt></pre><p>where the fields shall be as follows:</p><dl compact><dt><<i>current</i>></dt><dd>The character <tt>'+'</tt> identifies the job that would be used as a default for the <a href="../utilities/fg.html"><i>fg</i></a> or <a href="../utilities/bg.html"><i>bg</i></a> utilities; this job can also be specifiedusing the <i>job_id</i> %+ or <tt>"%%"</tt> . The character <tt>'-'</tt> identifies the job that would become the default if thecurrent default job were to exit; this job can also be specified using the <i>job_id</i> %-. For other jobs, this field is a<space>. At most one job can be identified with <tt>'+'</tt> and at most one job can be identified with <tt>'-'</tt> . Ifthere is any suspended job, then the current job shall be a suspended job. If there are at least two suspended jobs, then theprevious job also shall be a suspended job.</dd><dt><<i>job-number</i>></dt><dd>A number that can be used to identify the process group to the <a href="../utilities/wait.html"><i>wait</i></a>, <a href="../utilities/fg.html"><i>fg</i></a>, <a href="../utilities/bg.html"><i>bg</i></a>, and <a href="../utilities/kill.html"><i>kill</i></a> utilities. Using these utilities, the job can be identified by prefixing the job numberwith <tt>'%'</tt> .</dd><dt><<i>state</i>></dt><dd>One of the following strings (in the POSIX locale): <dl compact><dt><b>Running</b></dt><dd>Indicates that the job has not been suspended by a signal and has not exited.</dd><dt><b>Done</b></dt><dd>Indicates that the job completed and returned exit status zero.</dd><dt><b>Done</b>(<i>code</i>)</dt><dd>Indicates that the job completed normally and that it exited with the specified non-zero exit status, <i>code</i>, expressed asa decimal number.</dd><dt><b>Stopped</b></dt><dd>Indicates that the job was suspended by the SIGTSTP signal.</dd><dt><b>Stopped</b> (<b>SIGTSTP</b>)</dt><dd><br>Indicates that the job was suspended by the SIGTSTP signal.</dd><dt><b>Stopped</b> (<b>SIGSTOP</b>)</dt><dd><br>Indicates that the job was suspended by the SIGSTOP signal.</dd><dt><b>Stopped</b> (<b>SIGTTIN</b>)</dt><dd><br>Indicates that the job was suspended by the SIGTTIN signal.</dd><dt><b>Stopped</b> (<b>SIGTTOU</b>)</dt><dd><br>Indicates that the job was suspended by the SIGTTOU signal.</dd></dl><p>The implementation may substitute the string <b>Suspended</b> in place of <b>Stopped</b>. If the job was terminated by a signal,the format of <<i>state</i>> is unspecified, but it shall be visibly distinct from all of the other <<i>state</i>>formats shown here and shall indicate the name or description of the signal causing the termination.</p></dd><dt><<i>command</i>></dt><dd>The associated command that was given to the shell.</dd></dl><p>If the <b>-l</b> option is specified, a field containing the process group ID shall be inserted before the <<i>state</i>>field. Also, more processes in a process group may be output on separate lines, using only the process ID and<<i>command</i>> fields.</p></blockquote><h4><a name="tag_04_70_11"></a>STDERR</h4><blockquote><p>The standard error shall be used only for diagnostic messages.</p></blockquote><h4><a name="tag_04_70_12"></a>OUTPUT FILES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_70_13"></a>EXTENDED DESCRIPTION</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_70_14"></a>EXIT STATUS</h4><blockquote><p>The following exit values shall be returned:</p><dl compact><dt> 0</dt><dd>Successful completion.</dd><dt>>0</dt><dd>An error occurred.</dd></dl></blockquote><h4><a name="tag_04_70_15"></a>CONSEQUENCES OF ERRORS</h4><blockquote><p>Default.</p></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_04_70_16"></a>APPLICATION USAGE</h4><blockquote><p>The <b>-p</b> option is the only portable way to find out the process group of a job because different implementations havedifferent strategies for defining the process group of the job. Usage such as $( <i>jobs</i> <b>-p</b>) provides a way of referringto the process group of the job in an implementation-independent way.</p><p>The <i>jobs</i> utility does not work as expected when it is operating in its own utility execution environment because thatenvironment has no applicable jobs to manipulate. See the APPLICATION USAGE section for <a href="bg.html"><i>bg</i></a> . For thisreason, <i>jobs</i> is generally implemented as a shell regular built-in.</p></blockquote><h4><a name="tag_04_70_17"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_70_18"></a>RATIONALE</h4><blockquote><p>Both <tt>"%%"</tt> and <tt>"%+"</tt> are used to refer to the current job. Both forms are of equal validity-the <tt>"%%"</tt>mirroring <tt>"$$"</tt> and <tt>"%+"</tt> mirroring the output of <i>jobs</i>. Both forms reflect historical practice of theKornShell and the C shell with job control.</p><p>The job control features provided by <a href="../utilities/bg.html"><i>bg</i></a>, <a href="../utilities/fg.html"><i>fg</i></a>,and <i>jobs</i> are based on the KornShell. The standard developers examined the characteristics of the C shell versions of theseutilities and found that differences exist. Despite widespread use of the C shell, the KornShell versions were selected for thisvolume of IEEE Std 1003.1-2001 to maintain a degree of uniformity with the rest of the KornShell features selected (suchas the very popular command line editing features).</p><p>The <i>jobs</i> utility is not dependent on the job control option, as are the seemingly related <a href="../utilities/bg.html"><i>bg</i></a> and <a href="../utilities/fg.html"><i>fg</i></a> utilities because <i>jobs</i> is useful forexamining background jobs, regardless of the condition of job control. When the user has invoked a <a href="../utilities/set.html"><i>set</i></a> <b>+m</b> command and job control has been turned off, <i>jobs</i> can still beused to examine the background jobs associated with that current session. Similarly, <a href="../utilities/kill.html"><i>kill</i></a> can then be used to kill background jobs with <a href="../utilities/kill.html"><i>kill</i></a>% <<i>background job number</i>>.</p><p>The output for terminated jobs is left unspecified to accommodate various historical systems. The following formats have beenwitnessed:</p><ol><li><p><b>Killed</b>( <i>signal name</i>)</p></li><li><p><i>signal name</i></p></li><li><p><i>signal name</i>( <b>coredump</b>)</p></li><li><p><i>signal description</i>- <b>core dumped</b></p></li></ol><p>Most users should be able to understand these formats, although it means that applications have trouble parsing them.</p><p>The calculation of job IDs was not described since this would suggest an implementation, which may impose unnecessaryrestrictions.</p><p>In an early proposal, a <b>-n</b> option was included to "Display the status of jobs that have changed, exited, or stoppedsince the last status report". It was removed because the shell always writes any changed status of jobs before each prompt.</p></blockquote><h4><a name="tag_04_70_19"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_04_70_20"></a>SEE ALSO</h4><blockquote><p><a href="xcu_chap02.html#tag_02_12"><i>Shell Execution Environment</i></a> , <a href="bg.html"><i>bg</i></a> , <a href="fg.html"><i>fg</i></a> , <a href="kill.html"><i>kill</i>()</a> , <a href="wait.html"><i>wait</i>()</a></p></blockquote><h4><a name="tag_04_70_21"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4.</p></blockquote><h4><a name="tag_04_70_22"></a>Issue 6</h4><blockquote><p>This utility is marked as part of the User Portability Utilities option.</p><p>The JC shading is removed as job control is mandatory in this issue.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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