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Date:      Fri, 31 Oct 2008 12:27:37 -0700
From:      Fred Condo <fcondo@quinn.com>
To:        =?ISO-8859-1?Q?Fr=E9d=E9ric_Perrin?= <frederic.perrin@resel.fr>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Behaviour of su(1)
Message-ID:  <6F644950-947E-4D7E-85D7-E992E2A80A8D@quinn.com>
In-Reply-To: <86mygklilz.fsf@chameau.maisel.enst-bretagne.fr>
References:  <86mygklilz.fsf@chameau.maisel.enst-bretagne.fr>

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Use this syntax (both equivalent):
su - root
su -l root

You do have to specify the user with -l. Perhaps the man page could =20
clarify that.

On Oct 31, 2008, at 11:33 AM, Fr=E9d=E9ric Perrin wrote:

> Hello,
>
> When I =AB su - =BB to root (after being logged in as my normal user), =
the
> LOGNAME env variable is still set to my previous user, as in :
>
> ,----
> | fred@chameau:~% /usr/bin/su -l
> | Password:
> | root@chameau:~# echo $USER - $LOGNAME
> | root - fred
> `----
>
> As far as I can tell, this contradicts the fine manual that says :
>
> ,----
> | -l      Simulate a full login.  The environment is discarded =20
> except for
> |         HOME, SHELL, PATH, TERM, and USER.
> `----
>
> So I would have expected LOGNAME to be either empty or set by some =20
> shell
> startup script to be root. So, why is LOGNAME still equal to my =20
> previous
> user ? (and where is it set ? =AB grep -r LOGNAME /etc =BB doesn't =
turn up
> anything...)
>
> This is an issue because emacs, for instance, uses $LOGNAME to load =20=

> the
> init-file. I could always add =AB export LOGNAME=3Droot =BB to my =
shell
> startup file, but this doesn't quite feel right...
>
> GNU su (as it is ocnfigured in Debian at least) resets LOGNAME to root
> in the same situation. (and by the way, GNU su seems broken : if I =AB =
=20
> gsu
> -l root =BB, I always get a 'Password incorrect' answer).
>
> As a side question, is it considered bad practice to set root's shell
> and locales to something else then the default ?
>
> --=20
> Fred
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