huschi.net

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 (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 util-
       ity 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 environ-
       ment''; 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  op-
              erand  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 Vari-
              ables 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
       Default.
STDOUT
       The fg utility shall write the command line of the job to standard out-
       put 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  environment 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 char-
       acteristics 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 main-
       tain  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, 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 .

IEEE/The Open Group                  2003                               FG(1P)