升级Cmake（不用卸载原有的版本）

1、下载需要的版本

https://cmake.org/download/

2、解压、编译并安装到制定目录，修改环境变量

tar -zxvf cmake-3.20.0-rc1.tar.gz
cd cmake-3.20.0-rc1
./bootstrap --prefix=/opt/cmake-install
make 
make install


sudo gedit ~/.bashrc
#把下面两个命令加入~/.bashrc中
export PATH=/opt/cmake-install/bin:$PATH
export CMAKE_PREFIX_PATH=/opt/cmake-install:$CMAKE_PREFIX_PATH
#保存一下并运行
source ~/.bashrc