[francisck]

Actually a tool by the author of the book:

https://objective-see.org/products/knockknock.html

Recommend all of the tools that Patrick has created:

https://objective-see.org/tools.html

[notakio]

I will second both recommendations made here. Wardle's tools comprise a majority of my suggested macOS security stack on machines at work now.

[moomoo11]

Nice thanks for sharing