How to re-initialise the admin & user account, especially for password?

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Hi all, nice to see you. This is my 1st. time question after joining here.

I'm a beginner for Sage Math (for Mac OS X by .dmg), and tried to use it for a while. But yesterday, it hanged, and it went wrong. I have already re-installed the .dmg and deleted (moved) the ~/.sage. However I cannot login to the Sage notebook (from Launcher) since it seems I lost login information for my private account.

But when I execute the sage from command line, and also execute the notebook(), I succeeded to login as admin.

What should I do to recover the previous, comfortable use of Sage? What should I do to reset those accounts' info. from Sage command line or else.

Thanks in advance,