The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.

NAME

true - return true value

SYNOPSIS

true

DESCRIPTION

The true utility shall return with exit code zero.

OPTIONS

None.

OPERANDS

None.

STDIN

Not used.

INPUT FILES

None.

ENVIRONMENT VARIABLES

None.

ASYNCHRONOUS EVENTS

Default.

STDOUT

Not used.

STDERR

Not used.

OUTPUT FILES

None.

EXTENDED DESCRIPTION

None.

EXIT STATUS

Zero.

CONSEQUENCES OF ERRORS

None.

The following sections are informative.

APPLICATION USAGE

This utility is typically used in shell scripts, as shown in the EXAMPLES section. The special built-in utility : is sometimes more efficient than true.

EXAMPLES

This command is executed forever:

while true
do
    command
done

RATIONALE

The true utility has been retained in this volume of IEEE Std 1003.1-2001, even though the shell special built-in : provides similar functionality, because true is widely used in historical scripts and is less cryptic to novice script readers.

FUTURE DIRECTIONS

None.

SEE ALSO

false, Shell Commands

CHANGE HISTORY

First released in Issue 2.

Issue 6

IEEE Std 1003.1-2001/Cor 1-2002, item XCU/TC1/D6/39 is applied, replacing the terms ``None'' and ``Default'' from the STDERR and EXIT STATUS sections, respectively, with terms as defined in Utility Description Defaults.

End of informative text.
UNIX ® is a registered Trademark of The Open Group.
POSIX ® is a registered Trademark of The IEEE.
[ Main Index | XBD | XCU | XSH | XRAT ]