ssh-keygen -t ed25519 -C "you@example.com"

cat ~/.ssh/id_ed25519.pub

When you only have one account, using Git is easy—until you add more. Perhaps you organize coursework on Bitbucket, work with your team on GitLab, and contribute to open source on GitHub. All of a sudden, your Git IDs, SSH keys, and credentials begin to clash.

From the straightforward scenario of one account to a complex multi-account configuration, this tutorial takes you step-by-step through the management of SSH keys and Git identities across several accounts.

The Simple Case: One Git Account

If you only use one Git account, life is easy.

Generate an SSH key:

ssh-keygen -t ed25519 -C "you@example.com"

Add the key to your Git provider.

Copy your public key and paste it in your account settings:

cat ~/.ssh/id_ed25519.pub

Test your connection:

ssh -T git@github.com

You should see something like:

Hi username! You've successfully authenticated.

With one account, Git will automatically use this single SSH key. You’re done.

The Real World: Multiple Git Accounts

Once you manage multiple accounts, things get complicated:

Personal GitHub for side projects

Work Gitlab for company code

Another Work Github for another company project

School Bitbucket for academic repositories

Each service should have its own SSH key, so that:

You avoid identity confusion (wrong commits under the wrong name)

Access permissions remain separate

Your personal and professional lives stay cleanly divided

First Step: Create Separate SSH Keys

Let’s generate one SSH key per account:

# Personal GitHub
ssh-keygen -t ed25519 -C "personal@example.com" -f ~/.ssh/id_ed25519_github

# Work GitLab
ssh-keygen -t ed25519 -C "work@example.com" -f ~/.ssh/id_ed25519_gitlab_work

# Another Work Github
ssh-keygen -t ed25519 -C "work2@example.com" -f ~/.ssh/id_ed25519_github_work


# School Bitbucket
ssh-keygen -t ed25519 -C "school@example.edu" -f ~/.ssh/id_ed25519_bitbucket

You’ll now have files like these:

~/.ssh/
├── id_ed25519_github
├── id_ed25519_github.pub
├── id_ed25519_gitlab_work
├── id_ed25519_gitlab_work.pub
├── id_ed25519_github_work
├── id_ed25519_github_work.pub
├── id_ed25519_bitbucket
└── id_ed25519_bitbucket.pub

Add each public key (.pub file) to the matching Git account.

• Adding ssh key to Github
• Adding ssh key to Gitlab
• Adding SSH key to Bitbucket

Verifying that you can SSH into respective accounts

ssh -i ~/.ssh/id_ed25519_github git@github.com
ssh -i ~/.ssh/id_ed25519_gitlab_work git@gitlab.com
ssh -i ~/.ssh/id_ed25519_github_work git@github.com
ssh -i ~/.ssh/id_ed25519_bitbucket git@bitbucket.org

However, having to explicitly specify your ssh keys everytime is not particularly exciting and easy to forget.

Using ssh-agent: A Quick Way to Handle Multiple Keys

That’s where ssh-agent helps — it securely stores your decrypted private keys in memory.

Start the agent and add your keys:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519_github
ssh-add ~/.ssh/id_ed25519_gitlab_work
ssh-add ~/.ssh/id_ed25519_github_work
ssh-add ~/.ssh/id_ed25519_bitbucket

Check that your keys are loaded:

ssh-add -l

Now you can connect to your repositories without re-entering passwords every time.

However, the ssh-agent only runs for your current login or terminal session. If you restart your system, log out, or even open a new terminal, the agent may not remember your loaded keys. You’ll need to re-run the following code everytime you start a terminal session:

eval "$(ssh-agent -s)"
ssh-add ~/.ssh/id_ed25519_github
# further run ssh-add for every other keys we generated

(On Linux) To make it persistent, you can use a desktop keyring manager (like gnome-keyring), or configure your shell startup files (~/.bashrc, ~/.zshrc) to start and load your keys automatically.

Automate Key Selection with SSH Config (The Savior Step)

Create ~/.ssh/config file (if not already present) or add the following entries to it (if it already exists):

# Personal GitHub
Host github.com-personal
HostName github.com
User git
IdentityFile ~/.ssh/id_ed25519_github
IdentitiesOnly yes


# Work GitLab
Host gitlab.com-work
HostName gitlab.com
User git
IdentityFile ~/.ssh/id_ed25519_gitlab_work
IdentitiesOnly yes


# Work Github
Host github.com-work
HostName github.com
User git
IdentityFile ~/.ssh/id_ed25519_github_work
IdentitiesOnly yes


# School Bitbucket
Host bitbucket.org-school
HostName bitbucket.org
User git
IdentityFile ~/.ssh/id_ed25519_bitbucket
IdentitiesOnly yes

Now, use the aliases when cloning repositories, as per defined in your ~/.ssh/config file:

# Personal
git clone git@github.com-personal:username/personal-repo.git

# Work Gitlab
git clone git@gitlab.com-work:company/work-gitlab-repo.git

# Work Github
git clone git@github.com-work:company/work-github-repo.git


# School
git clone git@bitbucket.org-school:university/coursework.git

Now you can clone, pull and push your changes to Git Hosting Platforms without worrying about specifying the ssh private key explicitly or starting ssh-agent on every terminal session.

Bonus Tip

Always configure your Git username and email before making any commits — it saves you from headaches later. After cloning a repository, set your local username and email with the following commands:

git config --local user.name "your_name"
git config --local user.email "your_email"