/usr/bin/steamos-update

steamos-update

desktop@steamos:~$ cat /usr/bin/steamos-update 
#! /bin/sh

echo $$ > /tmp/steamos-update.pid

apt-get update -y -q
unattended-upgrade

# workaround for early images which didn't have nvidia-vdpau-driver:i386 preinstalled
if [ ! -f /usr/lib/i386-linux-gnu/vdpau/libvdpau_nvidia.so.1 ] ; then
    apt-get -y install nvidia-vdpau-driver:i386
fi

# workaround for early images which didn't have i965-va-driver:i386 preinstalled
if [ ! -f /usr/lib/i386-linux-gnu/dri/i965_drv_video.so ] ; then
    apt-get -y install i965-va-driver:i386
fi

# signal steam to refresh its inbox if we need a reboot
if [ -f /var/run/reboot-required ] && [ "`pidof -s steam`" != '' ] ; then
        STEAMPID=`pidof -s steam`
        STEAMUSER=`ps -p $STEAMPID -o user=`
        su $STEAMUSER -c steam steam://refreshinbox
fi

rm /tmp/steamos-update.pid