man break () - exit from for, while, or until loop

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 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 .