yqiang@zeus:~/ > sudo port clean --work
Can't map the URL 'file://.' to a port description file ("Could not find Portfile in .").
Please verify that the directory and portfile syntax are correct.
To use the current port, you must be in a port's directory.
(you might also see this message if a pseudo-port such as
outdated or installed expands to no ports).
Error: Unable to open port: Could not find Portfile in .