debain9添加nginx源

执行以下命令即可，以后apt upgrade更新软件，nginx也会自己更新。

sudo sh -c "echo 'deb http://nginx.org/packages/debian/ `lsb_release -cs` nginx' >> /etc/apt/sources.list"

sudo sh -c "echo 'deb-src http://nginx.org/packages/debian/ `lsb_release -cs` nginx' >> /etc/apt/sources.list"

curl http://nginx.org/keys/nginx_signing.key | apt-key add -

sudo apt update

sudo apt install nginx