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 .