break man page

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.

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.

Operands

See the Description.

Stdin

Not used.

Asynchronous Events

Default.

Stdout

Not used.

Stderr

The standard error shall be used only for diagnostic messages.

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.

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.

See Also

Section 2.14, Special Built-In Utilities

Info

2013 IEEE/The Open Group POSIX Programmer's Manual