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Section: POSIX Programmer's Manual (1P)
Updated: 2013
Index
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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
break
--- exit from for, while, or until loop
SYNOPSIS
break [n]
DESCRIPTION
The
break
utility shall exit from the smallest enclosing
for,
while,
or
until
loop, if any; or from the
nth
enclosing loop if
n
is specified. The value of
n
is an unsigned decimal integer greater than or equal to 1. The default
shall be equivalent to
n=1.
If
n
is greater than the number of enclosing loops, the outermost enclosing
loop shall be exited. Execution shall continue with the command
immediately following the loop.
OPTIONS
None.
OPERANDS
See the DESCRIPTION.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
None.
ASYNCHRONOUS EVENTS
Default.
STDOUT
Not used.
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
- 0
-
Successful completion.
- >0
-
The
n
value was not an unsigned decimal integer greater than or equal to 1.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
None.
EXAMPLES
for i in *
do
if test -d "$i"
then break
fi
done
RATIONALE
In early proposals, consideration was given to expanding the syntax of
break
and
continue
to refer to a label associated with the appropriate loop as a
preferable alternative to the
n
method. However, this volume of POSIX.1-2008 does reserve the name space of command names
ending with a
<colon>.
It is anticipated that a future implementation could take advantage of
this and provide something like:
-
outofloop: for i in a b c d e
do
for j in 0 1 2 3 4 5 6 7 8 9
do
if test -r "${i}${j}"
then break outofloop
fi
done
done
and that this might be standardized after implementation experience is
achieved.
FUTURE DIRECTIONS
None.
SEE ALSO
Section 2.14,
Special Built-In Utilities
COPYRIGHT
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 .
Index
- 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
-
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