在更新Ubuntu 16.04到18.04之后，我收到了“`apt更新”的错误

Question

以下是错误消息：

Err:1 https://esm.ubuntu.com/infra/ubuntu xenial-infra-security InRelease
  Could not resolve host: esm.ubuntu.com
Err:2 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu xenial InRelease
  Temporary failure resolving 'ppa.launchpad.net'
Err:3 http://ppa.launchpad.net/ubuntu-desktop/ubuntu-make/ubuntu xenial InRelease
  Temporary failure resolving 'ppa.launchpad.net'
Err:4 https://esm.ubuntu.com/infra/ubuntu xenial-infra-updates InRelease
  Could not resolve host: esm.ubuntu.com
Reading package lists... Done
W: Failed to fetch http://ppa.launchpad.net/deadsnakes/ppa/ubuntu/dists/xenial/InRelease  Temporary failure resolving 'ppa.launchpad.net'
W: Failed to fetch http://ppa.launchpad.net/ubuntu-desktop/ubuntu-make/ubuntu/dists/xenial/InRelease  Temporary failure resolving 'ppa.launchpad.net'
W: Failed to fetch https://esm.ubuntu.com/infra/ubuntu/dists/xenial-infra-security/InRelease  Could not resolve host: esm.ubuntu.com
W: Failed to fetch https://esm.ubuntu.com/infra/ubuntu/dists/xenial-infra-updates/InRelease  Could not resolve host: esm.ubuntu.com
W: Some index files failed to download. They have been ignored, or old ones used instead.

Answer 1

Step1。检查你的互联网连接。如果是坏的，切换到本地镜像。还请检查您的设备是否已正确设置为连接到Internet。

Step2。删除所有PPA并尝试sudo apt update && sudo apt full-upgrade

Step3。尝试手动将xenial更改为/etc/apt/sources.list中的bionic，将etc/apt/sources.d中的所有文件更改为sudo apt update。我以前没有尝试过这一点，因为这是"debian方式“，但它应该能工作。不过，作为预防措施，你应该备份你的文件。