Running X applications as root

Sometimes there is a need to run some rubbish graphical installer on your Debian system (e.g. Matlab). If we try:

sudo installer

we get an error:

Can't connect to X11 window server using ':0' as the value of the DISPLAY variable.

To fix it we need tell the xserver to accept connections from other users before we start the installation:

xhost +
sudo installer

and now it works fine!

nVidia proprietary drivers

As at June 2011 the recommended way to install nVidia drivers in Debian is to use the packages nvidia-glx + nvidia-kernel-dkms. The dkms package is triggered automagically every time linux headers are installed - and makes sure the kernel module is up to date (I don't really understand this in greater detail, because it works fine :)

So to make sure the drivers are installed with the current and future kernels you have to:

aptitude install linux-headers-2.6-686-pae nvidia-glx nvidia-kernel-dkms

where linux-headers-2.6-686-pae package will pull the latest headers, when a new kernel is installed.

Connecting to samba printers

To connect to a samba printer you have to install the samba client first:

aptitude install smbclient

Next you just create a new printer (e.g. using the web frontend for samba - localhost:631). From the list of connection types select:

Windows Printer via SAMBA

If its not in the list then you are missing some packages. Enter the connection url in the format:

smb:///username:password@server/printer

The last thing to do on the following screen is to select appropriate driver.

Usually, especially in a big organization you want to use the short windows names to connect to resources. To make it work samba needs to be a WINS client. In the samba configuration file
(/etc/samba/smb.conf) uncomment and correct the line:

wins server = 155.198.63.69

The above example is the Imperial College wins server.

Wpa_supplicant

To configure wpa_supplicant with the standard Debian ifupdown system one has to add the
wireless interface to /etc/network/interfaces file in the folowing way:

allow-hotplug wlan0
iface wlan0 inet manual
        wpa-driver wext
        wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf

Next you can copy a decent template for the config file:

mkdir /etc/wpa_supplicant
copy /usr/share/doc/wpasupplicant/examples/wpa-roam.conf /etc/wpa_supplicant/wpa_supplicant.conf

And you need to add your network according to the examples in the file. More examples are in the
/usr/share/doc/wpasupplicant/examples folder.

After a new network is added to the wpa_supplicant.config file one needs to tell the daemon to refresh the list:

wpa_action wlan0 reload

Samba shares

It is fairly easy to set up samba shares using one of the graphical tools (i.e. Dolphin).
However, it took me a while to figure out that you actually need to create a separate
samba password for the user that will connect to the share:

smbpasswd my_username