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



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may dif-
       fer (consult the corresponding Linux manual page for details of Linux behavior), or the interface  may  not  be
       implemented on Linux.

NAME
       fg - run jobs in the foreground

SYNOPSIS
       fg [job_id]

DESCRIPTION
       If  job control is enabled (see the description of set -m), the fg utility shall move a background job from the
       current environment (see 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 Asynchronous Lists .

OPTIONS
       None.

OPERANDS
       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 IEEE Std 1003.1-2001, Section 3.203,
              Job Control Job ID.


STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       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 IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the prece-
              dence 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 exam-
              ple, 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  writ-
              ten to standard error.

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


ASYNCHRONOUS EVENTS
       Default.

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


              "%s\n", <command>

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       None.

EXTENDED DESCRIPTION
       None.

EXIT STATUS
       The following exit values shall be returned:

        0     Successful completion.

       >0     An error occurred.


CONSEQUENCES OF ERRORS
       If  job  control  is  disabled, the fg utility shall exit with an error and no job shall be placed in the fore-
       ground.

       The following sections are informative.

APPLICATION USAGE
       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 . For this rea-
       son, fg is generally implemented as a shell regular built-in.

EXAMPLES
       None.

RATIONALE
       The extensions to the shell specified in this volume of IEEE Std 1003.1-2001 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 Korn-
       Shell. 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).

FUTURE DIRECTIONS
       None.

SEE ALSO
       Asynchronous Lists, Shell Execution Environment, bg, kill(), jobs, wait()

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Stan-
       dard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base  Specifica-
       tions  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 Stan-
       dard,  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 .



IEEE/The Open Group                  2003                               FG(1P)