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.
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-
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-
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.
Indicates that the job was suspended by the SIGTSTP signal.
Indicates that the job was suspended by the SIGSTOP signal.
Indicates that the job was suspended by the SIGTTIN signal.
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.
CONSEQUENCES OF ERRORS
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)