这是我现在的版本
lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.5 LTS
Release: 16.04
Codename: xenial
当我尝试
sudo do-release-upgrade
Error during update
A problem occurred during the update. This is usually some sort of
network problem, please check your network connection and retry.
Restoring original system state
Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
如果我尝试
ThinkPad-T520:~$ sudo apt-get upgrade
[sudo] password for usernameXYZ:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
-ThinkPad-T520:~$ lsb_release -a 没有可用的 LSB 模块。 分销商 ID：Ubuntu 描述：Ubuntu 16.04.5 LTS 发行版：16.04 代号：xenial
答案1
我认为这不是网络问题，而可能是程序问题。
要从命令行升级，您需要遵循以下步骤：
打开终端窗口Ctrl Alt t
发出命令sudo apt-get upgrade
输入您的用户密码
查看可用更新列表并决定是否要进行整个升级
要接受所有更新，请单击y键并点击Enter。
除此之外，还有一个新程序……感谢 itsfoss
答案2
可能需要先将 16.04 更新到最新状态，然后再升级到 18.04，请尝试一下。
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade