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Linux 2.6 - man page for jobs (linux section 1)

JOBS(P) 			    POSIX Programmer's Manual				  JOBS(P)

       jobs - display status of jobs in the current session

       jobs [-l| -p][job_id...]

       The  jobs  utility shall display the status of jobs that were started in the current shell
       environment; see Shell Execution Environment .

       When jobs reports the termination status of a job, the shell shall remove its  process  ID
       from  the list of those "known in the current shell execution environment''; see Asynchro-
       nous Lists .

       The jobs utility shall conform to the Base  Definitions	volume	of  IEEE Std 1003.1-2001,
       Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported:

       -l     (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.

       -p     Display only the process IDs for the process group leaders of the selected jobs.

       By  default,  the jobs utility shall display the status of all stopped jobs, running back-
       ground jobs and all jobs whose status has changed and have not been reported by the shell.

       The following operand shall be supported:

       job_id Specifies the jobs for which the status is to be displayed. If no job_id is  given,
	      the  status  information	for  all jobs shall be displayed. The format of job_id is
	      described in the Base Definitions volume of  IEEE Std 1003.1-2001,  Section  3.203,
	      Job Control Job ID.

       Not used.


       The following environment variables shall affect the execution of jobs:

       LANG   Provide  a  default  value for the internationalization variables that are unset or
	      null. (See the Base Definitions volume of IEEE Std 1003.1-2001, Section 8.2, Inter-
	      nationalization Variables for the precedence of internationalization variables used
	      to determine the values of locale categories.)

       LC_ALL If set to a non-empty string value, override the values of all the  other  interna-
	      tionalization variables.

	      Determine  the  locale for the interpretation of sequences of bytes of text data as
	      characters (for example, single-byte as opposed to multi-byte characters	in  argu-

	      Determine the locale that should be used to affect the format and contents of diag-
	      nostic messages written to standard error and informative messages written to stan-
	      dard output.

	      Determine the location of message catalogs for the processing of LC_MESSAGES .


       If the -p option is specified, the output shall consist of one line for each process ID:

	      "%d\n", <process ID>

       Otherwise, if the -l option is not specified, the output shall be a series of lines of the

	      "[%d] %c %s %s\n", <job-number>, <current>, <state>, <command>

       where the fields shall be as follows:

	      The character '+' identifies the job that would be used as a default for the fg  or
	      bg  utilities;  this  job  can  also be specified using the job_id %+ or "%%" . The
	      character '-' identifies the job that would  become  the	default  if  the  current
	      default  job  were to exit; this job can also be specified using the job_id %-. For
	      other jobs, this field is a <space>. At most one job can be identified with '+' and
	      at  most	one  job can be identified with '-' . If there is any suspended job, then
	      the current job shall be a suspended job. If there are at least two suspended jobs,
	      then the previous job also shall be a suspended job.

	      A  number  that  can be used to identify the process group to the wait, fg, bg, and
	      kill utilities. Using these utilities, the job can be identified by  prefixing  the
	      job number with '%' .

	      One of the following strings (in the POSIX locale):

	      Indicates that the job has not been suspended by a signal and has not exited.

	      Indicates that the job completed and returned exit status zero.

	      Indicates  that  the  job  completed normally and that it exited with the specified
	      non-zero exit status, code, expressed as a decimal number.

	      Indicates that the job was suspended by the SIGTSTP signal.

       Stopped (SIGTSTP)

	      Indicates that the job was suspended by the SIGTSTP signal.

       Stopped (SIGSTOP)

	      Indicates that the job was suspended by the SIGSTOP signal.

       Stopped (SIGTTIN)

	      Indicates that the job was suspended by the SIGTTIN signal.

       Stopped (SIGTTOU)

	      Indicates that the job was suspended by the SIGTTOU signal.

       The implementation may substitute the string Suspended in place of Stopped. If the job was
       terminated by a signal, the format of <state> is unspecified, but it shall be visibly dis-
       tinct from all of the other <state> formats shown here and  shall  indicate  the  name  or
       description of the signal causing the termination.

	      The associated command that was given to the shell.

       If  the	-l option is specified, a field containing the process group ID shall be inserted
       before the <state> field. Also, more processes in a process group may be output	on  sepa-
       rate lines, using only the process ID and <command> fields.

       The standard error shall be used only for diagnostic messages.



       The following exit values shall be returned:

	0     Successful completion.

       >0     An error occurred.


       The following sections are informative.

       The -p option is the only portable way to find out the process group of a job because dif-
       ferent implementations have different strategies for defining the  process  group  of  the
       job. Usage such as $( jobs -p) provides a way of referring to the process group of the job
       in an implementation-independent way.

       The jobs utility does not work as expected when it is operating in its own utility  execu-
       tion  environment  because  that environment has no applicable jobs to manipulate. See the
       APPLICATION USAGE section for bg . For this reason, jobs is  generally  implemented  as	a
       shell regular built-in.


       Both  "%%"  and "%+" are used to refer to the current job.  Both forms are of equal valid-
       ity-the "%%" mirroring "$$" and "%+" mirroring the output of  jobs.   Both  forms  reflect
       historical practice of the KornShell and the C shell with job control.

       The  job  control  features  provided  by bg, fg, and jobs are based on the KornShell. The
       standard developers examined the characteristics of the C shell versions of  these  utili-
       ties  and  found  that differences exist. Despite widespread use of the C shell, the Korn-
       Shell versions were selected for this volume of IEEE Std 1003.1-2001 to maintain a  degree
       of  uniformity  with the rest of the KornShell features selected (such as the very popular
       command line editing features).

       The jobs utility is not dependent on the job control option, as are the seemingly  related
       bg  and	fg  utilities because jobs is useful for examining background jobs, regardless of
       the condition of job control.  When the user has invoked a set +m command and job  control
       has been turned off, jobs can still be used to examine the background jobs associated with
       that current session.  Similarly, kill can then be used to kill background jobs with kill%
       <background job number>.

       The  output for terminated jobs is left unspecified to accommodate various historical sys-
       tems. The following formats have been witnessed:

	1. Killed( signal name)

	2. signal name

	3. signal name( coredump)

	4. signal description- core dumped

       Most users should be able to understand these formats, although it means that applications
       have trouble parsing them.

       The  calculation  of job IDs was not described since this would suggest an implementation,
       which may impose unnecessary restrictions.

       In an early proposal, a -n option was included to "Display the status of  jobs  that  have
       changed,  exited,  or  stopped  since  the last status report". It was removed because the
       shell always writes any changed status of jobs before each prompt.


       Shell Execution Environment , bg , fg , kill() , wait()

       Portions of this text are reprinted and	reproduced  in	electronic  form  from	IEEE  Std
       1003.1,	2003  Edition,	Standard  for Information Technology -- Portable Operating System
       Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003  by
       the  Institute  of  Electrical  and  Electronics Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE  and  The  Open  Group
       Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003					  JOBS(P)

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