fg(1p) — Linux manual page

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

FG(1P)                  POSIX Programmer's Manual                 FG(1P)

PROLOG         top

       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.

NAME         top

       fg — run jobs in the foreground

SYNOPSIS         top

       fg [job_id]

DESCRIPTION         top

       If job control is enabled (see the description of set -m), the fg
       utility shall move a background job from the current environment
       (see Section 2.12, Shell Execution Environment) into the
       foreground.

       Using fg to place a job into the foreground shall remove its
       process ID from the list of those ``known in the current shell
       execution environment''; see Section 2.9.3.1, Examples.

OPTIONS         top

       None.

OPERANDS         top

       The following operand shall be supported:

       job_id    Specify the job to be run as a foreground job. If no
                 job_id operand is given, the job_id for the job that
                 was most recently suspended, placed in the background,
                 or run as a background job shall be used. The format of
                 job_id is described in the Base Definitions volume of
                 POSIX.1‐2017, Section 3.204, Job Control Job ID.

STDIN         top

       Not used.

INPUT FILES         top

       None.

ENVIRONMENT VARIABLES         top

       The following environment variables shall affect the execution of
       fg:

       LANG      Provide a default value for the internationalization
                 variables that are unset or null. (See the Base
                 Definitions volume of POSIX.1‐2017, 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.

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

ASYNCHRONOUS EVENTS         top

       Default.

STDOUT         top

       The fg utility shall write the command line of the job to
       standard output in the following format:

           "%s\n", <command>

STDERR         top

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES         top

       None.

EXTENDED DESCRIPTION         top

       None.

EXIT STATUS         top

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS         top

       If job control is disabled, the fg utility shall exit with an
       error and no job shall be placed in the foreground.

       The following sections are informative.

APPLICATION USAGE         top

       The fg 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, fg is generally implemented
       as a shell regular built-in.

EXAMPLES         top

       None.

RATIONALE         top

       The extensions to the shell specified in this volume of
       POSIX.1‐2017 have mostly been based on features provided by the
       KornShell. The job control features provided by bg, fg, and jobs
       are also 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.1‐2017 to maintain a degree of uniformity with the rest of
       the KornShell features selected (such as the very popular command
       line editing features).

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       Section 2.9.3.1, Examples, Section 2.12, Shell Execution
       Environment, bg(1p), kill(1p), jobs(1p), wait(1p)

       The Base Definitions volume of POSIX.1‐2017, Section 3.204, Job
       Control Job ID, Chapter 8, Environment Variables

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 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 .

       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               2017                            FG(1P)

Pages that refer to this page: bg(1p)jobs(1p)