问题
Overall I am trying to inject key presses into the Ubuntu login screen from a separate shell. I have the machine (running Ubuntu 10.04) at the standard login screen and I am SSH'd into the machine as well. I've tried the following (from the SSH shell):
$ ps ax | grep X
2844 tty8 Ss+ 0:01 /usr/bin/X :0 -br -verbose -auth /var/run/gdm/auth-for-gdm-Gp2Rlq/database
$ export DISPLAY=:0
$ xdotool key Return
No protocol specified
Error: Can't open display: :0
Failed creating new xdo instance
This exact same method works once the machine is logged into Ubuntu, but it does not work for the login screen.
Ideally, I want to be able to finish the login from another shell. I do NOT want to use automatic login. I just want to be able to grab the correct display, and execute the key presses necessary to login.
Any help would be greatly appreciated.
Edited:
Thanks to the tip from n.m. I was able to get this working with:
export DISPLAY=:0
sudo xdotool key Return
This accomplishes what I wanted, but now I am wondering if there is a way to accomplish this without 'sudo'? Is there a flag I can enable/disable to get around this?
Thanks again for the help.
回答1:
You need authority to connect to the display. Note the -auth parameter to the X command. That's where the authority is.
Try this:
export XAUTHORITY=/var/run/gdm/auth-for-gdm-<whatever-it-is>/database
export DISPLAY=:0
xdotool key Return
You need to be root to be able to access the authority file.
See man xauth for (a lot) more information.
来源：https://stackoverflow.com/questions/10719987/accessing-the-x-display-for-ubuntu-gdm-login-screen