import getpass
print(getpass.getuser())
See the documentation of the getpass module.
getpass.getuser()
Return the “login name” of the user. Availability: Unix, Windows.
This function checks the environment variables LOGNAME, USER,
LNAME and USERNAME, in order, and
returns the value of the first one
which is set to a non-empty string. If
none are set, the login name from the
password database is returned on
systems which support the pwd module,
otherwise, an exception is raised.