Q: How to close a blank screen I tried to install bspwm to my ubuntu, when I restarted my computer, I logged in with bspwm session, the bad thing is, no keybindings work and I cannot open the session screen again, how can I close bspwm and open the unity and fix the problem ? Thank you.

A: Did you have a look at troubleshooting section?
Taken from their troubleshooting site:

There are a few ways to debug this. First, a blank screen is good.
  That means bspwm is running (usually).
I would confirm that your xinitrc looks something like
sxhkd & 
exec bspwm

The ampersand is important. Next, try spawning a
  terminal in your xinitrc to see if its getting positioned properly. It
  should appear somewhat "centered" on the screen. To do this, use this
  .xinitrc:
sxhkd & 
urxvt & 
exec bspwm 

If nothing shows up, that means you
  probably forgot to install urxvt. If it shows up but isn't centered or
  taking up most of your screen, that means BSPWM isn't starting
  properly. Make sure that you've chmod +x ~/.config/bspwm/bspwmrc.
Next, type pidof sxhkd in that terminal you spawned. It should return
  a process number. If it doesn't, that means sxhd isn't running. Try to
  be explicit and run sxhkd -c ~/.config/sxhkd/sxhkdrc. You could also
  try changing the Super key to something like Alt in your sxhkdrc and
  see if that helps. Another common problem is copying the text from the
  example files instead of physically copying the file over. Copying /
  pasting code usually leads to indentation issues which sxhkd can be
  sensitive to.


I hope this helps!
