Configure Multiple Github Account With SSH

By Sanket Gandhi on October 21, 2021

Generating SSH Keys

Generate SSH keys for the number of accounts with different name and email.

# Personal
ssh-keygen -t rsa -b 4096 -f ~/.ssh/<github_username>_github_personal -C "<[email protected]>"

# Work
ssh-keygen -t rsa -b 4096 -f ~/.ssh/<github_username>_github_work -C "<[email protected]>"

This will create public and private keys,
- Personal Keys: ~/.ssh/<github_username>_github_personal.pub and ~/.ssh/<github_username>_github_personal
- Works Keys: ~/.ssh/<github_username>_github_work.pub and ~/.ssh/<github_username>_github_work

Add public keys to GitHub

Login to github account
Copy your public ssh key (.pub extenion) and add it in your gihub account
```
pbcopy < ~/.ssh/<github_username>_github_personal.pub
```
Create New SSH Key on Github and paste copied key
Repeat above two steps for all your github accounts

Add SSH Keys

ssh-add ~/.ssh/<github_username>_github_personal
ssh-add ~/.ssh/<github_username>_github_work

Delete all cached keys that are added by ssh-add
```
ssh-add -D
```
Check all saved keys
```
ssh-add -l
```

Modify/Create SSH Config file

If you don't have ~/.ssh/config file then you can create and set proper permission
```
touch ~/.ssh/config
chmod 644 ~/.ssh/config
```

Add following configuration in config file,

Host personal.github.com
    HostName github.com
    User git
    PreferredAuthentications publickey
    IdentityFile <absolute_path_to_your_personal_github_private_ssh_key>
    UseKeychain yes # Comment this other than macOS user
    AddKeysToAgent yes

Host work.github.com
    HostName github.com
    User git
    PreferredAuthentications publickey
    IdentityFile <absolute_path_to_your_work_github_private_ssh_key>
    UseKeychain yes # Comment this other than macOS user
    AddKeysToAgent yes

You can now use git remote URL by changing [email protected] by [email protected]

Every time you clone git repo using different git account then you need to use like this,

git clone [email protected]:<username>/repository-name.git
cd repo
git config user.email "<email_address>"

You have to do this for every new repository. For existing repo,

git remote set-url origin [email protected]:<username>/repository-name.git

If you clone repo like this, git clone [email protected]:<username>/repository-name.git then it will use your public ssh key id which will use personal email address.

Setting `user.name` and `user.email` for all projects

You will need specific folder for all your work repo and personal/OSS repo. For e.g., ~/personal/ and ~/work/

Modify git config file,

    # ...
    # Personal gitconfig
    [includeIf "gitdir:~/personal/"]
        path = ~/.gitconfig-personal
    # Work gitconfig
    [includeIf "gitdir:~/work/"]
        path = ~/.gitconfig-work

Create ~/.gitconfig-personal and ~/.gitconfig-work files and add,

    [user]
        email = <personal_email>
        name = <Name>

Alternate Way For Above Step

Set alias in ~/.gitconfig file,

[alias]
setworkmail = "config user.email '<[email protected]>'"
setpersonalmail = "config user.email '<[email protected]>'"

From above alias we can do git setworkmail to change email this project only.

Single command to switch after cloning repo?

Clone repo with normal URL that github provides

Change remote host and email

To change remote host add alias in ~/.gitconfig

[alias]
    changeremotehost = !sh -c \"git remote -v | grep '$1.*fetch' | sed s/..fetch.// | sed s/$1/$2/ | xargs git remote set-url\"

Final alias in ~/.gitconfig file,

[alias]
setworkmail = "config user.email '<[email protected]>'"
setpersonalmail = "config user.email '<[email protected]>'"
changeremotehost = !sh -c \"git remote -v | grep '$1.*fetch' | sed s/..fetch.// | sed s/$1/$2/ | xargs git remote set-url\"
work = !sh -c \"git changeremotehost github.com work.github.com && git setworkmail\"
personal = !sh -c \"git changeremotehost github.com personal.github.com && git setpersonalmail\"

Output

git clone [email protected]:username/repo.git
cd repo
git work

Credits

Cheers!