This old vncserver hack, can make life easy. I remember the old problem .. how can you generate graphs in R in cronjobs without going via the postscript format?

 1. vncserver
 2. enter password
 3. remove all in  ~/.vnc/xstartup that is not needed
 4. work:
    DISPLAY=:1 R
 5. vncserver -kill :DISPLAYNUMBER_FROM_STEP_1

Thanks to Stefan!