Originální popis anglicky:
jobs - display status of jobs in the current session
Návod, kniha: POSIX Programmer's Manual
jobs [-l| -p][job_id...]
utility shall display the status of jobs that were started in
the current shell environment; see Shell Execution Environment
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 Asynchronous Lists
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:
- (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.
- 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:
- 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
- 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, Internationalization
Variables for the precedence of internationalization variables used to
determine the values of locale categories.)
- If set to a non-empty string value, override the values of
all the other internationalization 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 arguments).
- 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.
- 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:
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:
- 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
- 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
. If the job was terminated by a signal, the format of <
> 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.
- 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
The standard error shall be used only for diagnostic messages.
The following exit values shall be returned:
- Successful completion.
- An error occurred.
The following sections are informative.
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
a way of referring to the process group of the job in an
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
. For this
is generally implemented as a shell regular built-in.
are used to refer to the
current job. Both forms are of equal validity-the "%%"
mirroring the output
. Both forms reflect historical practice of the KornShell and
the C shell with job control.
The job control features provided by bg
, and jobs
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 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).
utility is not dependent on the job control option, as are the
seemingly related bg
utilities because jobs
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
The output for terminated jobs is left unspecified to accommodate various
historical systems. The following formats have been witnessed:
- Killed( signal name)
- signal name
- signal name( coredump)
- 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
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 original
Standard can be obtained online at http://www.opengroup.org/unix/online.html