錯誤：startx命令錯誤：
Server is already active for display 0：
檢查是否只有一個X server在運行。
ps aux | grep
cat /tmp/.X0-lock如果有類似的輸出，則表明確實有一個Xserver正在運行
If you see an output like:
root 2283 0.5 5.1 27796 6536 ? S Apr21 59:03 [X]
解決方法：
To start a second server on the same system you have to give it a different dislay
number.
If you start your servers using startx you can do：
startx – :1
沒有Xserver在運行時，刪除tmp/.X0-lock文件，然後再startx
If you are sure there is no other server running on your system and above ps command
indicates that no server with this PID is running, you should remove the file
/tmp/.X0-lock by doing (as ‘root’):
rm -rf /tmp/.X0-lock
需要用root權限才能刪除，其中-f 表示強制刪除。
