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

None.

STDIN

None.

INPUT FILES

None.

ENVIRONMENT VARIABLES

None.

ASYNCHRONOUS EVENTS

None.

STDOUT

None.

STDERR

None.

OUTPUT FILES

None.

EXTENDED DESCRIPTION

None.

EXIT STATUS

Zero.

CONSEQUENCES OF ERRORS

None.

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

None.