因为系统环境变量崩溃，进行重做了系统，全部还原，在本机重新安装了显卡驱动、cuda等，具体系统版本如下。
系统环境：ubuntu18.04
显卡：rtx2080ti
cuda版本：10.2
安装RTX2080ti显卡驱动
1、 ubuntu 18.04默认安装了第三方开源的驱动程序nouveau，安装nvidia显卡驱动首先需要禁用nouveau，不然会碰到冲突的问题，导致无法安装nvidia显卡驱动。
# 首先编辑文件blacklist.conf
sudo vim /etc/modprobe.d/blacklist.conf
# 在文件最后部分插入以下两行内容
blacklist nouveau
options nouveau modeset=0
#更新系统
sudo update-initramfs -u
#重启系统（一定要重启）
reboot
#验证nouveau是否已禁用，若没有提示任何信息则是已经禁用
lsmod | grep nouveau
2、下载安装显卡驱动，在官网找到相应版本的驱动下载即可，http://www.nvidia.cn/page/home.html，将下载的驱动拷贝到/home目录下
# 下载的2080Ti驱动如下
440.82.run
3、在ubuntu按ctrl+alt+f1进入命令行界面，关闭图形界面，卸载原有的驱动
# 这个是关闭图形界面，不执行会出错
sudo service lightdm stop
# 然后卸载掉原有驱动：
sudo apt-get remove nvidia-*
4、给驱动文件赋予权限并进行安装，在安装过程中执行默认选项即可
# 进行赋予权限
sudo chmod a+x NVIDIA-Linux-x86_64-396.18.run
# 安装
sudo ./440.82.run
5、挂在显卡驱动，进行测试，进行重启
# 挂在显卡驱动
modprobe nvidia
# 检查驱动是否安装成功
nvidia-smi
# 重启
sudo reboot
安装Cuda10.2
1、安装cuda10.2，在弹出的界面输入accept，因为我们已经安装了显卡驱动，所以就不需要在安装显卡驱动了
# 安装
sudo ./cuda_10.2.89_440.33.01_linux.run
2、配置环境变量
# 打开bashrc文件
sudo gedit ~/.bashrc
# 添加三条路径
export CUDA_HOME=/usr/local/cuda
export PATH=$PATH:$CUDA_HOME/bin
export LD_LIBRARY_PATH=/usr/local/cuda-10.2/lib64${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}
#让配置生效
source ~/.bashrc
3、查看是否安装成功
# 输入
nvcc -V
# 安装成功
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2019 NVIDIA Corporation
Built on Wed_Oct_23_19:24:38_PDT_2019
Cuda compilation tools, release 10.2, V10.2.89
安装Cudnn
1、从https://developer.nvidia.com/cudnn下载相应版本的cudnn
2、下载后解压，将cudnn文件拷贝到cuda中的相应目录
#将cuda/include/cudnn.h文件复制到/usr/local/cuda-10.2/include文件夹
#将cuda/lib64/下所有文件复制到/usr/local/cuda-10.2/lib64文件夹中
cp cuda/include/cudnn.h /usr/local/cuda-10.2/include
cp cuda/lib64/* /usr/local/cuda-10.2/lib64
# 给予权限
sudo chmod a+r /usr/local/cuda/include/cudnn.h
sudo chmod a+r /usr/local/cuda/lib64/libcudnn*
3、验证是否安装成功
cd /usr/local/cuda-10.2/samples/1_Utilities/deviceQuery
sudo make
sudo ./deviceQuery
输出如下设备信息表示成功
./deviceQuery Starting...
CUDA Device Query (Runtime API) version (CUDART static linking)
Detected 2 CUDA Capable device(s)
Device 0: "GeForce RTX 2080 SUPER"
CUDA Driver Version / Runtime Version 10.2 / 10.2
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 7979 MBytes (8366784512 bytes)
(48) Multiprocessors, ( 64) CUDA Cores/MP: 3072 CUDA Cores
GPU Max Clock rate: 1845 MHz (1.85 GHz)
Memory Clock rate: 7751 Mhz
Memory Bus Width: 256-bit
L2 Cache Size: 4194304 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: Yes
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 1 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
Device 1: "GeForce RTX 2080 SUPER"
CUDA Driver Version / Runtime Version 10.2 / 10.2
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 7982 MBytes (8370061312 bytes)
(48) Multiprocessors, ( 64) CUDA Cores/MP: 3072 CUDA Cores
GPU Max Clock rate: 1845 MHz (1.85 GHz)
Memory Clock rate: 7751 Mhz
Memory Bus Width: 256-bit
L2 Cache Size: 4194304 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: No
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 2 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
> Peer access from GeForce RTX 2080 SUPER (GPU0) -> GeForce RTX 2080 SUPER (GPU1) : No
> Peer access from GeForce RTX 2080 SUPER (GPU1) -> GeForce RTX 2080 SUPER (GPU0) : No
deviceQuery, CUDA Driver = CUDART, CUDA Driver Version = 10.2, CUDA Runtime Version = 10.2, NumDevs = 2
