Stop Manually Copying SSH Public Keys: One-Click Import from GitHub on Linux Servers

Introduction

A highlight of the Ubuntu installer (Subiquity) is that you can automatically import SSH public keys just by entering a GitHub username.

It greatly simplifies the initial setup of a new server, saving you the hassle of manually copying and pasting that long string of SSH Public Key.

How It Works

GitHub provides a public SSH public key access endpoint for every user.

Anyone's public keys are public information; you just need to visit the following URL pattern in a browser or terminal: https://github.com/你的用户名.keys

When you enter a username, the Ubuntu installer performs something like the following in the background:

1. Access https://github.com/username.keys via a network request.
2. Retrieve the plaintext public key list returned by that page.
3. Append these public keys to the corresponding user's ~/.ssh/authorized_keys file on the server.
4. Ensure the .ssh directory and authorized_keys file have the correct permissions (usually 700 and 600).

How to Do It?

Method 1: Use ssh-import-id (Most Recommended)

That Ubuntu feature actually invokes the ssh-import-id tool, which is also available in Debian's official repositories.

1. Install the tool:

   Bash

   sudo apt update && sudo apt install ssh-import-id -y
   

2. Import the public key:

   Bash

   ssh-import-id gh:你的GitHub用户名
   

   Note: The gh: prefix stands for GitHub; it also supports Launchpad (using lp:).

Method 2: Pure Manual Universal Command (No Extra Tools Needed)

If you don't want to install extra packages, you can also get it done directly with curl and a pipe:

Bash

mkdir -p ~/.ssh && chmod 700 ~/.ssh
curl -L https://github.com/你的用户名.keys >> ~/.ssh/authorized_keys
chmod 600 ~/.ssh/authorized_keys

Tips

• This approach depends on GitHub's availability and network connectivity. If you're on a company intranet or in a special network environment, make sure the server can access github.com normally.
• Multi-platform support: Besides GitHub, GitLab also provides a similar feature, with the URL format https://gitlab.com/用户名.keys.
• Automated deployment: If you frequently tinker with servers, you can put the curl command above into your initialization script or Dockerfile to achieve truly "frictionless" configuration.