colon - null utility
: [argument ...]
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.
None.
See the DESCRIPTION.
Not used.
None.
None.
Default.
Not used.
The standard error shall be used only for diagnostic messages.
None.
None.
Zero.
Default.
None.
: ${X=abc} if false then : else echo $X fi abcAs with any of the special built-ins, the null utility can also have variable assignments and redirections associated with it, such as:
x=y : > zwhich sets variable x to the value y (so that it persists after the null utility completes) and creates or truncates file z.
None.
None.
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.