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 "$i" then break fi done
RATIONALE
In early proposals, consideration was given to expanding the syntax
of break and continue to refer to a label associated with
the appropriate loop as a preferable
alternative to the n method. However, this volume of IEEE Std 1003.1-2001
does reserve the name space of command
names ending with a colon. It is anticipated that a future implementation
could take advantage of this and provide something
like:
outofloop: for i in a b c d e
do
for j in 0 1 2 3 4 5 6 7 8 9
do
if test -r "${i}${j}"
then break outofloop
fi
done
done
and that this might be standardized after implementation experience
is achieved.
FUTURE DIRECTIONS
None.
SEE ALSO
Special Built-In Utilities
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 .
