Operation not permitted "sudo ditto -v to folder /usr/bin"
The folder /usr/bin/ is (like other system folders in El Capitan) protected by SIP (System Integrity Protection).

You may either boot to Recovery Mode, disable System Integrity Protection with csrutil disable entered in Terminal.app and after rebooting copy the executable or use the folder /usr/local/bin instead. You may have to adjust your path in the latter case.