执行 apt-get update 报错：
N: Skipping acquire of configured file 'nginx/binary-i386/Packages' as repository 'http://nginx.org/packages/ubuntu bionic InRelease' doesn't support architecture 'i386'
解决方法
编辑文件 /etc/apt/sources.list.d/nginx.list。
原来的
deb http://nginx.org/packages/ubuntu/ bionic nginx
deb-src http://nginx.org/packages/ubuntu/ bionic nginx
改为
deb [arch=amd64] http://nginx.org/packages/ubuntu/ bionic nginx
deb-src http://nginx.org/packages/ubuntu/ bionic nginx
增加 [arch=amd64] 后，重新执行 apt-get update 命令，这次警告消息没有了。