colon

The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.

#### 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 nothing 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

> Special Built-In Utilities

#### CHANGE HISTORY

#### Issue 6

> IEEE Std 1003.1-2001/Cor 1-2002, item XCU/TC1/D6/5 is applied so that the reference page sections use terms as described in the Utility Description Defaults ( Utility Description Defaults ). No change in behavior is intended.

End of informative text.

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