MacOS: Run script before shutdown

MacOSLogoutHook.txt

Create a file:
$ pico /Users/Shared/logoutHook.sh

File content:
#!/bin/bash
say 'Hasta la vista baby!'

Set exuction permission:
$ sudo chmod +x /Users/Shared/logoutHook.sh

Script hook:
$ sudo defaults write com.apple.loginwindow LogoutHook /Users/Shared/logoutHook.sh

To remove the hook:
$ sudo defaults delete com.apple.loginwindow LogoutHook