Manage Multiple SSH Keys

Scenario

I have multiple SSH keys, want to manage them without any trouble. I can do it in various ways:

1. creating a directory for ssh key and switch every time I need to or even create a script for that.
2. use the same ssh key for all accounts like Github, Bitbucket, Gitlab, etc. But there is one catch, which is I cannot use the same ssh key on the same server like Github.
3. Create a separate ssh key for all accounts and manage it using ssh config, which I am going to use in this post.

Assumptions

1. You have basic knowledge about Git and SSH.
2. All your generated ssh keys will be inside the ~/.ssh directory.

Step to create ssh config

1. Generate ssh key for your account. The following command will generate private and public keys.

ssh-keygen -t ed25519 -C "<EMAIL_ADDRESS>"

1. Rename your ssh key and give it some meaningful name like in my case:

mv ~/.ssh/id_ed25519 ~/.ssh/github_id_ed25519

1. Repeat 1 & 2 Steps for all your accounts

2. Create config file inside .ssh directory

touch ~/.ssh/config

1. Add the following configuration inside your config file. You can add/remove based on your needs:

    # GitHub Account 1
    Host github.com
    HostName github.com
    User <USER_NAME_1>
    IdentityFile ~/.ssh/github_id_ed25519
   
    # Github Account 2
    Host github.com-<USER_NAME_2>
    HostName github.com
    User <USER_NAME_2>
    IdentityFile ~/.ssh/github2_id_ed25519
   
    # Gitlab Account
    Host gitlab.com
    HostName gitlab.com
    User <USER_NAME>
    IdentityFile ~/.ssh/gitlab_id_ed25519
   
    # Bitbucket Account
    Host bitbucket.org
    HostName bitbucket.org
    User <USER_NAME>
    IdentityFile ~/.ssh/bucket_id_ed25519
   

Note:

For the Github account, we have defined two accounts.

• One with default HostName
• Another with extra content append to default HostName, which is USERNAME_2

Also, note that I have added dash (-) after the HostName.

How to use it

It’s simple. Just do what you were doing with a single SSH key for all accounts including GitHub Account 1.

But for GitHub Account 2, we have to handle it differently.

Let’s say if we have a URL like this git@github.com:<USER_NAME_2>/project.git

then we need to append git@github.com -<USER_NAME_2> :/project.git. It's the only thing that we have to do before we use it.

# For Github Account 2
# Instead of this
git clone git@github.com:<USER_NAME_2>/project.git

# We have to use it in this way
git clone git@github.com-<USER_NAME_2>:<USER_NAME_2>/project.git

Some useful SSH command

• If your ssh-agent failed then you can restart it using the following command

eval $(ssh-agent -s)

• If you want to list all registered keys

ssh-add -l

• If you want to clear all registered keys

ssh-add -D