Disable Linux builtin command using enable command.

   The step by step Linux command example below show how to disable Linux builtin command using the enable command.  By disabling the Linux builtin command, it allow you to execute command that using same name as Linux builtin command to be execute without specifying the full pathname to the binary file of that command.  The step by step command example below use pwd command as an example to show the output when we use the pwd command from Linux built command and after that we disable the Linux builtin command in this case pwd command and then execute the pwd command from the disk command (not builtin command).