TRUE
Section: POSIX Programmer's Manual (1P)
Updated: 2017
Page Index
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
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 POSIX.1-2017, 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
Section 2.9,
Shell Commands,
false
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 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 .
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 .