The '-U' command line option has no config-based equivalent.
I'd like for buildout.cfg to be able to indicate that the user's ~/.buildout/
For symmetry, I think that '-u' should be added as a command line option which indicates the user's default.cfg *SHOULD* be used. This (like '-U') would override any related setting in the config. But in the absence of either '-U' or '-u', the presence in the config of a keyword such as 'userdefaults' (userdefaults=
As an added bonus, '-U' and '-u' would adhere to the ad hoc convention of the uppercase letter argument being the negative setting and the lowercase letter argument being the positive setting. Furthermore, the default buildout behavior (if no command line argument is present and no config variable is provided) would continue to be 'use the default.cfg', so any existing scripts and such would continue working normally.