TRUE(1P) POSIX Programmer's Manual TRUE(1P)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.
NAMEtrue — return true value
SYNOPSIStrueDESCRIPTION
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 EXAM‐
PLES section. The special built-in utility : is sometimes more effi‐
cient 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.1‐2008, 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, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 TRUE(1P)
