解决ubuntu老版本源失效
备份下旧的源
cp /etc/apt/sources.list /etc/apt/sources.list_backup
将所有源的主域替换为http://old-releases.ubuntu.com/ubuntu/
http://old-releases.ubuntu.com/ubuntu/
更新
apt-get update
备份下旧的源
cp /etc/apt/sources.list /etc/apt/sources.list_backup
将所有源的主域替换为http://old-releases.ubuntu.com/ubuntu/
http://old-releases.ubuntu.com/ubuntu/
更新
apt-get update