我打开 GUI 更新管理器进行更新。但它给出了这个窗口：
于是我点击了“再试一次”，结果还是一样。然后我点击了“设置...”看看我是否弄坏了什么东西。
我没发现有什么问题。但我注意到一些源代码正在下载。我不希望它下载。所以我取消勾选了源代码，然后单击“关闭”。它显示了这个窗口：
因此我重新加载它并出现此错误：
请注意，我确实有互联网连接。我可以安装：
tim@Hairy16:~$ apt install traceroute
Reading package lists... Done
Building dependency tree
Reading state information... Done
Get:1 http://gb.archive.ubuntu.com/ubuntu xenial/universe amd64 traceroute amd64 1:2.0.21-1 [45.5 kB]
Fetched 45.5 kB in 0s (280 kB/s)
Selecting previously unselected package traceroute.
(Reading database ... 158453 files and directories currently installed.)
Preparing to unpack .../traceroute_1%3a2.0.21-1_amd64.deb ...
Unpacking traceroute (1:2.0.21-1) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up traceroute (1:2.0.21-1) ...
跟踪路由谷歌：
tim@Hairy16:~$ traceroute google.com
traceroute to google.com (216.58.198.110), 30 hops max, 60 byte packets
1 dsldevice.lan (192.168.1.254) 11.259 ms 11.259 ms 11.304 ms
2 lo0-central10.pcl-ag05.plus.net (195.166.128.186) 29.279 ms 29.496 ms 30.662 ms
3 link-a-central10.pcl-gw01.plus.net (212.159.2.176) 30.736 ms 30.807 ms 30.874 ms
4 xe-1-2-0.pcl-cr01.plus.net (212.159.0.208) 34.146 ms 34.217 ms 34.886 ms
5 ae2.pcl-cr02.plus.net (195.166.129.7) 36.757 ms ae1.ptw-cr01.plus.net (195.166.129.0) 35.837 ms ae2.pcl-cr02.plus.net (195.166.129.7) 36.820 ms
6 72.14.222.97 (72.14.222.97) 36.585 ms 16.235 ms ae1.ptw-cr02.plus.net (195.166.129.2) 17.139 ms
7 72.14.223.32 (72.14.223.32) 17.047 ms 30.030 ms 24.532 ms
8 64.233.174.113 (64.233.174.113) 24.435 ms 64.233.175.155 (64.233.175.155) 26.854 ms 64.233.174.83 (64.233.174.83) 26.929 ms
9 64.233.175.155 (64.233.175.155) 26.271 ms 27.269 ms lhr25s07-in-f14.1e100.net (216.58.198.110) 26.737 ms
然后 ping Google：
tim@Hairy16:~$ ping google.com
PING google.com (216.58.208.142) 56(84) bytes of data.
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=1 ttl=55 time=12.5 ms
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=2 ttl=55 time=12.4 ms
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=3 ttl=55 time=87.8 ms
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=4 ttl=55 time=12.6 ms
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=5 ttl=55 time=118 ms
64 bytes from lhr25s08-in-f14.1e100.net (216.58.208.142): icmp_seq=6 ttl=55 time=12.2 ms
--- google.com ping statistics ---
6 packets transmitted, 6 received, 0% packet loss, time 5007ms
rtt min/avg/max/mdev = 12.291/42.734/118.675/43.701 ms
如何通过 GUI 更新？
答案1
从我在 pastebin 中看到的情况来看，您的 /etc/apt/sources.list 文件可能有重复的条目。我会使用 nano 或 gedit 等文本编辑器手动删除这些行。
无法下载存储库信息是由于 sources.list 文件中的存储库不存在 - 看起来 Xenial 的 extras 存储库尚不存在。删除该行
deb http://extras.ubuntu.com/ubuntu xenial main
应该可以修复更新。
之后我也会执行“apt-get clean”。