At the moment I'm trying to remote control my machine and command and ctrl do not seem to be working properly. Is there some type of 'keyboard sniffer' functionality so I can see exactly what is and is not being received?

  • I was looking for the same thing, It's called "keystroke visualizer". – Ihab Shoully Dec 1 '15 at 0:20

I don't know if the built-in keyboard viewer is sophisticated enough, but it should highlight pressed keys.

If you do not see those options, make sure it is checked off under your System Preferences > Keyboard

enter image description here

There are also apps like Keycastr that display bezel elements for pressed keys.

  • no need in terminal. need octal/hex numbers. otherwise you don't know what is being sent. – mathtick Mar 2 '19 at 12:51
  • In 10.15.5 this checkbox appears to be moved to Preferences -> Keyboard -> Input Sources -> "Show Input menu in menu bar" – AndyP Jun 20 '20 at 2:18

The application Key Codes from Many Tricks, available for free from the App Store, displays the key code, unicode value, and modifier keys state for any key combination pressed on your computer. If you need more extensive information than that provided by the Keyboard Viewer, you might find it helpful.

  • 3
    I tried Key Codes and it doesn't work for media keys. – Dan Mandle Mar 11 '15 at 22:20
  • This is exactly what I needed to debug a firmware of int'l keyboard. – epx May 18 '19 at 2:22
  • Let's try on macOS. – Smeterlink May 20 '20 at 23:21

Karabiner Elements includes an Event Viewer that works really well. For example, Apple's Keyboard Viewer just ignores keypad keys; Karabiner-EventViewer shows them.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .