[CentOS] su command

[Steve Lindemann]

On 5/8/2014 7:57 AM, Jerry Geis wrote:
> I am running pulseaudio on centOS 6.5
> audio works fine as the user.
> running the command
> aplay /usr/share/sounds/alsa/Front_Center.wav
> works fine.
>
> when I login as root and run the command
> su user -c "aplay /usr/share/sounds/alsa/Front_Center.wav"
> it does not work.
>
> I thought su actually runs as that user...
> is there some "magic" to su I don't know about?
> How might I get that to work ?
>
>
> Thanks,
>
> jerry

If the program works normally from that user's account then you need 
that user's environment and to get that you use the - (dash) switch.  So 
your command would look like:

   su - user -c "aplay /usr/share/sounds/alsa/Front_Center.wav"

This is why when we switch user to root we use: su -
...to ensure we get root's environment.  See the man page for su.
--
steve