http://it.dennyhalim.com/2008/10/linux-automatic-login-startx-and.html

.bashrc

#!/bin/bash
# http://it.dennyhalim.com/2008/10/linux-automatic-login-startx-and.html
# paste into your ~/.bashrc and it just works.
# it will startx / startxfce when you login at tty1
# it can also logout/shutdown after you close x.

file=/tmp/.X0-lock
 #check if x is running
if [[ -e $file ]]
then
    echo "Ctrl+Alt+F7 to switch to XWindow"
#only run X if login at tty1
elif [ $(tty) == /dev/tty1 ]; then 
    startx
    # exit #to logout automatically after x closed
           #if you use exit and you have autologin, it loop and restart X 
    /sbin/halt 	#to shutdown automatically after x closed
    		#you should sudo chmod +s /sbin/halt for this to works correctly
fi