无法更新Ubuntu 18.04

Question

当我运行命令：root@versinator:~# apt-get update时，我得到以下错误：

Hit:1 http://us-east1.gce.archive.ubuntu.com/ubuntu bionic InRelease
Hit:2 http://us-east1.gce.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:3 http://us-east1.gce.archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:4 http://archive.canonical.com/ubuntu bionic InRelease
Hit:6 http://security.ubuntu.com/ubuntu bionic-security InRelease
Hit:7 http://ppa.launchpad.net/webupd8team/y-ppa-manager/ubuntu bionic InRelease
Get:5 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease [17.5 kB]
Err:5 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1E9377A2BA9EF27F
Reading package lists... Done
W: GPG error: http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1E9377A2BA9EF27F
E: The repository 'http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

如何删除此错误并返回到安全状态？

Answer 1

"apt-get更新“的问题是您丢失了公钥1E9377A2BA9EF27F。您可以通过执行以下操作将此键添加到您的密钥环中：

sudo apt-key adv --recv-key 1E9377A2BA9EF27F

它会向你展示这样的东西：

Executing: /tmp/apt-key-gpghome.IA65nrxcnz/gpg.1.sh --recv-key 1E9377A2BA9EF27F
gpg: key 1E9377A2BA9EF27F: public key "Launchpad Toolchain builds" imported
gpg: Total number processed: 1
gpg:               imported: 1

现在您可以运行"apt-get update“或"apt update"，它还将获取"http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease”的索引。

Answer 2

编辑文件：

sudo nano /etc/apt/sources.list

将#作为一行的第一个字符。

然后，只需做一个更新：

sudo apt update

如果错误消失，您可以删除所观察到的行。

Answer 3

转到synaptic，然后设置选项卡存储库，然后是其他软件。取消选中ppa前面的框为Ubuntu-工具链-r。再装子弹。