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.
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.1-2008, 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
CHANGE HISTORY
First released in Issue 2.
Issue 6
IEEE Std 1003.1-2001 (“POSIX.1”)/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.