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 differ (con-
       sult 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 precedence  of  international-
              ization 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 stan-
              dard 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 foreground.

       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 envi-
       ronment has no applicable jobs to manipulate. See the APPLICATION USAGE section for bg . For this reason, 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  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).

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,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                        FG(1P)