$ sudo pip install
[sudo] password for xenocampanoli: 
The directory '/home/xenocampanoli/.cache/pip/http' or its parent directory is not owned by the current user and the cache has been disabled. Please check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
The directory '/home/xenocampanoli/.cache/pip' or its parent directory is not owned by the current user and caching wheels has been disabled. check the permissions and owner of that directory. If executing pip with sudo, you may want sudo's -H flag.
You must give at least one requirement to install (see "pip help install")