前提：服务器中已安装了cuda-9.0
接下来安装cuda-9.2
1. 下载cuda-9.2
选择cuda版本
https://developer.nvidia.com/cuda-toolkit-archive
选择平台
安装
安装过程（出现more [0%]要按回车）
摘自：https://blog.csdn.net/ksws0292756/article/details/80120561
#先执行下面的命令安装相关依赖，
#否则会出现`Missing recommended library`错误
sudo apt-get install freeglut3-dev build-essential libx11-dev libxmu-dev libxi-dev libgl1-mesa-glx libglu1-mesa libglu1-mesa-dev
sudo sh cuda_8.0.61_375.26_linux.run #开始安装
#..一堆协议说明...
#直接按q退出协议说明.
zerozone@zerozone: accept/decline/quit: accept #接受协议
Install NVIDIA Accelerated Graphics Driver for Linux-x86_64 375.26?
y)es/(n)o/(q)uit: n #是否显卡驱动包，由于已经安装显卡驱动，选择n
Install the CUDA 8.0 Toolkit?
(y)es/(n)o/(q)uit: y #是否安装工具包，选择y
Enter Toolkit Location
[ default is /usr/local/cuda-8.0 ]: #工具包安装地址，默认回车即可
Do you want to install a symbolic link at /usr/local/cuda?
(y)es/(n)o/(q)uit: y #添加链接**注意这个连接，如果你之前安装过另一个版本的cuda，除非你确定想要用这个新版本的cuda，否则这里就建议选no，因为指定该链接后会将cuda指向这个新的版本**
Install the CUDA 8.0 Samples?
(y)es/(n)o/(q)uit: y #安装样例
Enter CUDA Samples Location
[ default is /root ]: #样例安装地址默认即可
# ***安装信息***
Installing the CUDA Toolkit in /usr/local/cuda-8.0 ...
Missing recommended library: libXi.so
Missing recommended library: libXmu.so
#注意，这里出现了Missing recommended library错误，
#是因为博主在第一次安装时，没有添加最开始的那条安装相关依赖的指令，
#之后我添加了依赖后，再次安装，就没有Missing错误了
Installing the CUDA Samples in /root ...
Copying samples to /root/NVIDIA_CUDA-8.0_Samples now...
Finished copying samples.
===========
= Summary =
===========
Driver: Not Selected
Toolkit: Installed in /usr/local/cuda-8.0
Samples: Installed in /root, but missing recommended libraries
Please make sure that
- PATH includes /usr/local/cuda-8.0/bin
- LD_LIBRARY_PATH includes /usr/local/cuda-8.0/lib64, or, add /usr/local/cuda-8.0/lib64 to /etc/ld.so.conf and run ldconfig as root
To uninstall the CUDA Toolkit, run the uninstall script in /usr/local/cuda-8.0/bin
Please see CUDA_Installation_Guide_Linux.pdf in /usr/local/cuda-8.0/doc/pdf for detailed information on setting up CUDA.
***WARNING: Incomplete installation! This installation did not install the CUDA Driver. A driver of version at least 361.00 is required for CUDA 8.0 functionality to work.
To install the driver using this installer, run the following command, replacing <CudaInstaller> with the name of this run file:
sudo <CudaInstaller>.run -silent -driver
Logfile is /tmp/cuda_install_6388.log
# ***安装完成***
2. 配置CUDA相关环境变量
打开/usr/local， 可以看到cuda9.2安装包已存在
cuda是个软连接，将原来的软连接删除，建立新的指向cuda-9.2的软连接
sudo rm -rf cuda
sudo ln -s /usr/local/cuda-9.2 /usr/local/cuda
查看此时cuda指向：
修改~/.bashrc文件：
将终端关闭，开启一个新的终端,输入：
source ~/.bashrc
成功！ 查看nvcc版本：
若以后想要使用切换不同版本的cuda，只需
（1）将cuda的软连接删除，再重新建立指向新版本的cuda-x.x的软连接
（2）打开新的终端执行source ~/.bashrc
即可。