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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
JOBS(1P) POSIX Programmer's Manual JOBS(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
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 Section 2.12, 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 Section 2.9.3.1, Examples.
The jobs utility shall conform to the Base Definitions volume of
POSIX.1‐2008, 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 background 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 POSIX.1‐2008, Section 3.204,
Job Control Job ID.
Not used.
None.
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 POSIX.1‐2008, Section 8.2, Internationalization
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 internationalization variables.
LC_CTYPE 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 arguments).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error and informative messages written to standard
output.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
Default.
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 form:
"[%d] %c %s %s\n", <job-number>, <current>, <state>, <command>
where the fields shall be as follows:
<current> 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.
<job-number>
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 '%'.
<state> One of the following strings (in the POSIX locale):
Running Indicates that the job has not been suspended by
a signal and has not exited.
Done Indicates that the job completed and returned
exit status zero.
Done(code)
Indicates that the job completed normally and
that it exited with the specified non-zero exit
status, code, expressed as a decimal number.
Stopped 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 distinct from all of the other <state> formats
shown here and shall indicate the name or description of
the signal causing the termination.
<command> 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 separate lines, using only the
process ID and <command> fields.
The standard error shall be used only for diagnostic messages.
None.
None.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
Default.
The following sections are informative.
The −p option is the only portable way to find out the process group
of a job because different 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 execution environment because that environment has no
applicable jobs to manipulate. See the APPLICATION USAGE section for
bg(1p). For this reason, jobs is generally implemented as a shell
regular built-in.
None.
Both "%%" and "%+" are used to refer to the current job. Both forms
are of equal validity—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 utilities and found that differences
exist. Despite widespread use of the C shell, the KornShell versions
were selected for this volume of POSIX.1‐2008 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 systems. 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.
None.
Section 2.12, Shell Execution Environment, bg(1p), fg(1p), kill(1p),
wait(1p)
The Base Definitions volume of POSIX.1‐2008, Section 3.204, Job
Control Job ID, Chapter 8, Environment Variables, Section 12.2,
Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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 original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 JOBS(1P)
Pages that refer to this page: bg(1p), fg(1p)