true1p
Return true value
Usage
true
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.
Overview
The true utility shall return with exit code zero.
Options
None.
Operands
None.
Stdin
Not used.
Input files
None.
Environment
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.