shasum has no output, why? Here's the terminal command and output:  

douglas@machine Desktop % shasum -a 256 /Users/douglas/Desktop/TinkerTool.app  
shasum: /Users/douglas/Desktop/TinkerTool.app: 

which shasum:
/usr/bin/shasum
Tinkertool.app is just a folder. You need to run it on the actual app. Your command should be shasum -a 256 /Users/douglas/Desktop/TinkerTool.app/Contents/MacOS/Tinkertool

You can get to the actual app by right-clicking on Tinkertool.app and selecting "Show package contents" and navigating to the actual app.