Ubuntu 常见错误及其解决方案

1. Fix Missing GPG Key Apt Repository Errors (NO_PUBKEY)

• UNIX Tutorial for Beginners

ERROR: cannot download default sources list from: https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list Website may be down.

报错原因是 GitHub 的 raw.githubusercontent.com 无法连接，需要解决 GitHub 的 raw.githubusercontent.com 无法连接问题

通过 IPAddress.com 首页,输入 raw.githubusercontent.com 查询到真实IP地址
修改 hosts Ubuntu，

$ sudo code /etc/hosts

添加以下内容保存即可

199.232.28.133 raw.githubusercontent.com

在ubuntu更新时，出现错误E: Some index files failed to download, they have been ignored, or old ones used inst

在ubuntu更新时，出现错误E: Some index files failed to download, they have been ignored, or old ones used inst
http://www.ilovn.com/topic/ubuntu-update-error-esome-index-files-failed-to-download-they-have-been-ignored-or-old-ones-used-inst/
在ubuntu更新时，执行命令 sudo apt-get update，出现错误E: Some index files failed to download, they have been ignored, or old ones used instead
可以将目录下/var/lib/apt/lists/partial/所有的文件清掉

$ sudo rm /var/lib/apt/lists/* -vf

再次运行 apt-get update