Mac OSx terminal sudo

I think for security reason, OSx require user not use blank password to run sudo command.

The content below is referred from Apple website:

 Mac OS X v10.6 or later, if you press the Return key at the password prompt without entering a password, the message "Sorry, try again." will be displayed and you will be prompted for a password again.

If your administrator account has no password (a blank password), you must give that user a password before using thesudocommand.

After you are done using thesudocommand, you can change your account password again, although it is recommended that your administrator account have a non-blank password.