This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface
Contents
Application Usage
None.
Asynchronous Events
Default.
Consequences Of Errors
Default.
Thefollowingsectionsareinformative.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 .
IEEE/The Open Group 2017 COLON(1POSIX)
Description
This utility shall only expand command arguments. It is used when a command is needed, as in the then
condition of an if command, but nothing is to be done by the command.
Environment Variables
None.
Examples
: ${X=abc}
if false
then :
else echo $X
fi
abc
As with any of the special built-ins, the null utility can also have variable assignments and
redirections associated with it, such as:
x=y : > z
which sets variable x to the value y (so that it persists after the null utility completes) and creates
or truncates file z.
Exit Status
Zero.
Extended Description
None.
Future Directions
None.
Input Files
None.
Name
colon — null utility
Operands
See the DESCRIPTION.
Options
None.
Output Files
None.
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.
Rationale
None.
See Also
Section2.14, SpecialBuilt-InUtilities
Stderr
The standard error shall be used only for diagnostic messages.
Stdin
Not used.
Stdout
Not used.
Synopsis
: [argument...]