I believe that su user -c command throws away the environment
su - user -c command executes the user .profile
Tom Lane wrote:
> "Bender, Cheryl" <cbender@mriresearch.org> writes:
>
>>I need to add an alternate db location for my 7.3.4 server (running on
>>FreeBSD 5.2 Release)
>>I thought I did everything according to the administrator's guide, but I
>>fail at createdb.
>
>
> How are you starting the postmaster, exactly?
>
> A lot of people use start scripts that boil down to something like
>
> su - postgres -c "postmaster ..."
>
> The "su -" means "throw away the existing environment variables and
> adopt the environment that would be obtained by logging in from scratch
> as postgres". So it doesn't matter *what* you do before executing such
> a script; the environment variables you have won't affect what the
> postmaster gets.
>
> What you have to do to play with such a script is put the export or
> setenv command into whatever "~postgres/.profile" file will be read by
> the standard shell that su will invoke. This is what you want anyway,
> really, since anything you do any other way will be lost in a reboot.
>
> This'll all get a lot easier in 8.0, thankfully (no more dependence
> on environment variables).
>
> regards, tom lane
>
> ---------------------------(end of broadcast)---------------------------
> TIP 2: you can get off all lists at once with the unregister command
> (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
>
