在Ubuntu環境想安裝NVIDIA顯卡驅動的時候，可能會遇到下面的錯誤：
ERROR: You appear to be running an X server; please exit X before installing.
這個時候，就需要按照下面的命令執行了。
service lightdm stop
init 3
# Install driver
./NVIDIA-Linux-x86_64-418.56.run
安裝成功以後，可以用下面的命令檢查一下
watch -n 1 nvidia-smibash
如果已經安裝好了，會出現下面的這樣表格：
Every 1.0s: nvidia-smi Thu Sep 19 13:35:39 2019
Thu Sep 19 13:35:39 2019
+-----------------------------------------------------------------------------+
| NVIDIA-SMI 418.56 Driver Version: 418.56 CUDA Version: 10.1 |
|-------------------------------+----------------------+----------------------+
| GPU Name Persistence-M| Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap| Memory-Usage | GPU-Util Compute M. |
|===============================+======================+======================|
| 0 GeForce RTX 208... Off | 00000000:04:00.0 Off | N/A |
| 55% 59C P2 130W / 250W | 8841MiB / 10989MiB | 48% Default |
+-------------------------------+----------------------+----------------------+
| 1 GeForce RTX 208... Off | 00000000:05:00.0 Off | N/A |
| 52% 57C P2 148W / 250W | 8841MiB / 10989MiB | 59% Default |
+-------------------------------+----------------------+----------------------+
| 2 GeForce RTX 208... Off | 00000000:84:00.0 Off | N/A |
| 50% 56C P2 114W / 250W | 8845MiB / 10989MiB | 47% Default |
+-------------------------------+----------------------+----------------------+
| 3 GeForce RTX 208... Off | 00000000:85:00.0 Off | N/A |
| 53% 58C P2 121W / 250W | 8841MiB / 10989MiB | 44% Default |
+-------------------------------+----------------------+----------------------+