See below line for what I am trying to accomplish.

/ip firewall filter add in-interface=$hsinterface dst-port=53 protocol=udp place-before=1 action=drop

Would like to logical NOT this global variable but have had no joy so far. Is it possible to Logical NOT a global variable?

Thanks in advance,

just perform the usual string operation when trying to set some value. See scripting section in manual on how to concatenate the value from variable to a string.

I think you can do something like this:

Awesome, thanks.

cool! thanks