mirror of https://github.com/mkerrisk/man-pages
153 lines
4.5 KiB
Groff
153 lines
4.5 KiB
Groff
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "FG" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" fg
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.SH NAME
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fg \- run jobs in the foreground
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.SH SYNOPSIS
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.LP
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\fBfg\fP \fB[\fP\fIjob_id\fP\fB]\fP\fB\fP
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.SH DESCRIPTION
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.LP
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If job control is enabled (see the description of \fIset\fP \fB-m\fP),
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the
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\fIfg\fP utility shall move a background job from the current environment
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(see \fIShell
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Execution Environment\fP ) into the foreground.
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.LP
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Using \fIfg\fP to place a job into the foreground shall remove its
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process ID from the list of those "known in the current
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shell execution environment''; see \fIAsynchronous Lists\fP .
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.SH OPTIONS
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.LP
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None.
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.SH OPERANDS
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.LP
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The following operand shall be supported:
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.TP 7
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\fIjob_id\fP
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Specify the job to be run as a foreground job. If no \fIjob_id\fP
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operand is given, the \fIjob_id\fP for the job that was
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most recently suspended, placed in the background, or run as a background
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job shall be used. The format of \fIjob_id\fP is
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described in the Base Definitions volume of IEEE\ Std\ 1003.1-2001,
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Section 3.203, Job Control Job ID.
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.sp
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.SH STDIN
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.LP
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Not used.
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.SH INPUT FILES
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.LP
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None.
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.SH ENVIRONMENT VARIABLES
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.LP
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The following environment variables shall affect the execution of
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\fIfg\fP:
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.TP 7
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\fILANG\fP
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Provide a default value for the internationalization variables that
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are unset or null. (See the Base Definitions volume of
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IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables
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for
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the precedence of internationalization variables used to determine
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the values of locale categories.)
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.TP 7
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\fILC_ALL\fP
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If set to a non-empty string value, override the values of all the
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other internationalization variables.
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.TP 7
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\fILC_CTYPE\fP
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Determine the locale for the interpretation of sequences of bytes
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of text data as characters (for example, single-byte as
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opposed to multi-byte characters in arguments).
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.TP 7
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\fILC_MESSAGES\fP
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Determine the locale that should be used to affect the format and
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contents of diagnostic messages written to standard
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error.
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.TP 7
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\fINLSPATH\fP
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Determine the location of message catalogs for the processing of \fILC_MESSAGES
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\&.\fP
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.sp
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.SH ASYNCHRONOUS EVENTS
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.LP
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Default.
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.SH STDOUT
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.LP
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The \fIfg\fP utility shall write the command line of the job to standard
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output in the following format:
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.sp
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.RS
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.nf
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\fB"%s\\n", <\fP\fIcommand\fP\fB>
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\fP
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.fi
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.RE
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.SH STDERR
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.LP
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The standard error shall be used only for diagnostic messages.
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.SH OUTPUT FILES
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.LP
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None.
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.SH EXTENDED DESCRIPTION
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.LP
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None.
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.SH EXIT STATUS
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.LP
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The following exit values shall be returned:
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.TP 7
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\ 0
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Successful completion.
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.TP 7
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>0
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An error occurred.
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.sp
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.SH CONSEQUENCES OF ERRORS
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.LP
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If job control is disabled, the \fIfg\fP utility shall exit with an
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error and no job shall be placed in the foreground.
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.LP
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\fIThe following sections are informative.\fP
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.SH APPLICATION USAGE
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.LP
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The \fIfg\fP utility does not work as expected when it is operating
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in its own utility execution environment because that
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environment has no applicable jobs to manipulate. See the APPLICATION
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USAGE section for \fIbg\fP . For this
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reason, \fIfg\fP is generally implemented as a shell regular built-in.
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.SH EXAMPLES
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.LP
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None.
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.SH RATIONALE
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.LP
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The extensions to the shell specified in this volume of IEEE\ Std\ 1003.1-2001
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have mostly been based on features
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provided by the KornShell. The job control features provided by \fIbg\fP,
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\fIfg\fP, and \fIjobs\fP are also based on the KornShell. The standard
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developers examined the characteristics
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of the C shell versions of these utilities and found that differences
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exist. Despite widespread use of the C shell, the KornShell
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versions were selected for this volume of IEEE\ Std\ 1003.1-2001 to
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maintain a degree of uniformity with the rest of the
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KornShell features selected (such as the very popular command line
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editing features).
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.SH FUTURE DIRECTIONS
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.LP
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None.
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.SH SEE ALSO
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.LP
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\fIAsynchronous Lists\fP , \fIShell Execution
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Environment\fP , \fIbg\fP , \fIkill\fP() , \fIjobs\fP
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, \fIwait\fP()
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.SH COPYRIGHT
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Portions of this text are reprinted and reproduced in electronic form
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from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
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-- Portable Operating System Interface (POSIX), The Open Group Base
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Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
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Electrical and Electronics Engineers, Inc and The Open Group. In the
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event of any discrepancy between this version and the original IEEE and
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The Open Group Standard, the original IEEE and The Open Group Standard
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is the referee document. The original Standard can be obtained online at
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http://www.opengroup.org/unix/online.html .
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