macOS hidden unix folders and files
Hidden folders and files not visible in Finder
If after an upgrade or update certain functions are no longer working like Crontab tasks, most likely it is because of new security features or existing permissions were reset.
To provide permission for binaries to be ran like anything under
/usr/sbin/, it can be done through System Preferences -> Security & Privacy -> Privacy -> Full Disk Access.
To get /usr/sbin/ folder to show up, press CMD+SHIFT+G.