W: GPG error: http://packages.ros.org/ros/ubuntu bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY F42ED6FBAB17C654

这个错误是由于缺少ROS存储库的公钥导致的。你可以使用以下命令来解决这个问题：

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-key F42ED6FBAB17C654

运行以上命令将下载并安装ROS存储库的公钥。然后，再次尝试更新软件源和安装ROS：

sudo apt-get update
sudo apt-get install ros-melodic-desktop-full

相关问题

Fetched 1,027 kB in 5s (190 kB/s) Reading package lists... Done W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://packages.ros.org/ros/ubuntu bionic InRelease: The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <info@osrfoundation.org> W: Failed to fetch http://packages.ros.org/ros/ubuntu/dists/bionic/InRelease The following signatures were invalid: EXPKEYSIG F42ED6FBAB17C654 Open Robotics <info@osrfoundation.org> W: Some index files failed to download. They have been ignored, or old ones used instead.

这是一个常见的错误，可能是由于 GPG 密钥过期或未正确安装所致。您可以尝试以下步骤来解决这个问题：

1. 打开终端，输入以下命令以删除旧的 GPG 密钥：

   sudo apt-key del F42ED6FBAB17C654

2. 输入以下命令以获取新的 GPG 密钥：

   sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

3. 输入以下命令以更新包列表：

   sudo apt update

4. 如果仍然出现问题，则可以尝试更改软件源，将其更改为其他可行的软件源。

命令报错： sudo apt update Hit:1 http://mirrors.aliyun.com/ubuntu bionic InRelease Hit:2 http://mirrors.aliyun.com/ubuntu bionic-updates InRelease Hit:3 http://mirrors.aliyun.com/ubuntu bionic-backports InRelease Hit:4 http://mirrors.aliyun.com/ubuntu bionic-security InRelease Get:5 https://mirrors.aliyun.com/docker-ce/linux/ubuntu bionic InRelease [64.4 kB] Ign:6 https://pkg.jenkins.io/debian-stable binary/ InRelease Get:7 https://pkg.jenkins.io/debian-stable binary/ Release [2,044 B] Get:8 https://pkg.jenkins.io/debian-stable binary/ Release.gpg [833 B] Ign:8 https://pkg.jenkins.io/debian-stable binary/ Release.gpg Reading package lists... Done W: GPG error: https://pkg.jenkins.io/debian-stable binary/ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 5BA31D57EF5975CA E: The repository 'http://pkg.jenkins.io/debian-stable binary/ Release' 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.

这个错误是因为缺少 Jenkins 仓库的公钥。您可以按照以下步骤导入公钥并解决问题：

1. 打开终端。
2. 下载 Jenkins 的公钥。输入以下命令并按回车：

   wget -q -O - https://pkg.jenkins.io/debian/jenkins.io.key | sudo apt-key add -

3. 重新运行 `sudo apt update` 命令以更新软件包列表。

现在，您应该能够成功更新软件包列表，然后继续安装 Jenkins。请尝试执行之前的步骤，并告诉我是否还遇到问题。