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.1‐2008,
                 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.1‐2008, 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.1‐2008
       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.1‐2008 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.1‐2008, 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, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) 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.unix.org/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                 2013                              FG(1P)