hasValue command

Got the tki command, hasValue, working:

Execute the first argument if the file/property/value tuple is present.

Four required arguments: command, file, property, value.
If the value is a pathname, it must begin with '@'.

Alternately, when the file is a dictionary, a key can be given in placeof the property. (In this case, the '@' is ignored if present--the valueis always a pathname.)