The -not_if option returns true or false and is the start of the IF
block structure. The
-not_if option is like the
-if option except the results are reversed.
-if ':HGT:' is true if the match inventory contains the string ':HGT:', and
the next block is executed. The option -not_if ':HGT:' does the opposite
and does not execute the next block.
See -if for details about the IF block structure.
X is a regular expression
returns true if X is not in the match inventory, false otherwise
See also: -not,