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COLON(1P)                  POSIX Programmer's Manual                 COLON(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.
NAME
       colon -- null utility
SYNOPSIS
       : [argument...]
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 noth-
       ing is to be done by the command.
OPTIONS
       None.
OPERANDS
       See the DESCRIPTION.
STDIN
       Not used.
INPUT FILES
       None.
ENVIRONMENT VARIABLES
       None.
ASYNCHRONOUS EVENTS
       Default.
STDOUT
       Not used.
STDERR
       The standard error shall be used only for diagnostic messages.
OUTPUT FILES
       None.
EXTENDED DESCRIPTION
       None.
EXIT STATUS
       Zero.
CONSEQUENCES OF ERRORS
       Default.
       The following sections are informative.
APPLICATION USAGE
       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.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       Section 2.14, Special Built-In Utilities
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                            COLON(1P)