How to view your SSH public key on Linux: Two simple methods September 12, 2023

If you are managing remote servers, using SSH (Secure Shell) is essential. SSH keys provide a secure and convenient way to authenticate, and at times, you may need to view your SSH public key. In this guide, we will walk you through two easy methods to view your SSH public key on a Linux system.

First, let us understand what an SSH public key is.

An SSH public key is part of a pair (public and private) that you create for secure communication with a server. The public key is shared with the server, letting you establish a secure connection without needing a password.

Method 1: Viewing SSH Public Key Using the ‘cat’ Command

The simplest way to view your SSH public key is by using the ‘cat’ command. Follow these steps:

1. Open a terminal on your Linux machine.
2. Execute the following command to display your SSH public key:

   cat ~/.ssh/id_rsa.pub

3. Copy the displayed key from the terminal and paste it where required (e.g., server configuration).Note: This command assumes your public key is located in the ‘~/.ssh/’ directory, which is the default for most Linux distributions. If your key is stored in a different location, adjust the path accordingly.

Method 2: Viewing SSH Public Key Using ‘ssh-agent’ and ‘ssh-add’

This method is slightly more advanced and beneficial if you are using ‘ssh-agent’ to manage your SSH keys:

1. Open a terminal.
2. Run the subsequent command to view your SSH public key through the agent:

   ssh-agent sh -c ‘ssh-add; ssh-add -L’

3. After positive authentication, the public key linked with the agent will be displayed.
4. Copy the SSH public key from the terminal output and use it as needed.

When and Why Should You View Your SSH Public Key?

You might need to view your SSH public key when:

1. Adding the key to a new server for secure login.
2. Sharing the key with a remote service (like GitHub or cloud providers).
3. Verifying that the correct key is being used.

Troubleshooting Common Issues:

1. SSH Key Not Found:
   If you receive a message indicating that the key file does not exist, ensure you’ve generated an SSH key pair using:

   ssh-keygen -t rsa

   This command will create a new key pair in the default location (~/.ssh/).

2. Multiple SSH Keys:
   If you have multiple SSH keys, you can specify the exact key file by replacing id_rsa.pub in the cat command with the appropriate file name.

Tips for Secure SSH Key Management:

1. Protect your private key:
   Never share your private key (id_rsa). It must remain secure on your machine.
2. Use a passphrase:
   When generating a key pair, adding a passphrase improves security, requiring it to unlock the private key.
3. Backup your keys:
   Confirm that you have a secure backup of your SSH keys to avoid losing access to your servers.

Conclusion:

Viewing your SSH public key on Linux is a simple process with both the ‘cat’ command and ‘ssh-agent’ methods. Whether you are configuring a new server or managing SSH keys, knowing how to access your public key is essential for secure remote access.

Need to enable SSH on your VPS? Read our guide on How to Enable SSH on VPS through WHM