mirror of https://github.com/mkerrisk/man-pages
121 lines
2.8 KiB
Groff
121 lines
2.8 KiB
Groff
.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved
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.TH "BREAK" 1P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
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.\" break
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.SH NAME
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break \- exit from for, while, or until loop
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.SH SYNOPSIS
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.LP
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\fBbreak\fP \fB[\fP\fIn\fP\fB]\fP
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.SH DESCRIPTION
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.LP
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The \fIbreak\fP utility shall exit from the smallest enclosing \fBfor\fP,
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\fBwhile\fP, or \fBuntil\fP loop, if any; or from
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the \fIn\fPth enclosing loop if \fIn\fP is specified. The value of
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\fIn\fP is an unsigned decimal integer greater than or equal
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to 1. The default shall be equivalent to \fIn\fP=1. If \fIn\fP is
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greater than the number of enclosing loops, the outermost
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enclosing loop shall be exited. Execution shall continue with the
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command immediately following the loop.
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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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See the DESCRIPTION.
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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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None.
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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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Not used.
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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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.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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The \fIn\fP value was not an unsigned decimal integer greater than
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or equal to 1.
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.sp
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.SH CONSEQUENCES OF ERRORS
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.LP
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Default.
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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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None.
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.SH EXAMPLES
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.sp
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.RS
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.nf
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\fBfor i in * do
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if test -d "$i" then break fi done
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\fP
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.fi
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.RE
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.SH RATIONALE
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.LP
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In early proposals, consideration was given to expanding the syntax
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of \fIbreak\fP and \fIcontinue\fP to refer to a label associated with
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the appropriate loop as a preferable
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alternative to the \fIn\fP method. However, this volume of IEEE\ Std\ 1003.1-2001
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does reserve the name space of command
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names ending with a colon. It is anticipated that a future implementation
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could take advantage of this and provide something
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like:
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.sp
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.RS
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.nf
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\fBoutofloop: for i in a b c d e
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do
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for j in 0 1 2 3 4 5 6 7 8 9
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do
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if test -r "${i}${j}"
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then break outofloop
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fi
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done
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done
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\fP
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.fi
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.RE
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.LP
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and that this might be standardized after implementation experience
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is achieved.
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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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\fISpecial Built-In Utilities\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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