How to configure (and use) two ssh keys for Github

This blog is for all the fresh interns starting off contributing to a repository that’s not open source and the team won’t give you access to repository on your personal email but on your_name@corporate_domain.com. So basically we’ll have to configure two ssh key’s on the same machine and here’s how :

How to setup two different ssh keys on same machine?

Firstly generate two ssh keys for corresponding accounts , here’s github guide for that

# Default github account: personal_username
Host github.com
   HostName github.com
   IdentityFile ~/.ssh/personal_key
   IdentitiesOnly yes
   
# Other github account: professional_username
Host github-professional_username
   HostName github.com
   IdentityFile ~/.ssh/professional_key
   IdentitiesOnly yes

Just add ssh private keys to you agent by :

$ ssh-add ~/.ssh/personal_key
$ ssh-add ~/.ssh/professional_key

Now git commands will default to use your personal key as identifier but to specify your professional key for work you could finally clone that repository by :

$ git clone git@github-professional_username:org/project.git /project/path

Alternatively if you want to use a specific key to run any github command just prepend you git command with GIT_SSH_COMMAND environment variable like :

$ GIT_SSH_COMMAND='ssh -i ~/.ssh/professional_key' git push origin master

Kidding about pushing to master 😂, however if you want to setup a specific key for a specific repository(say you have only 3–4 repository for work on your machine)

Make changes to that repository’s git config by

$ vi .git/config

Add the following configuration to that file

[user]
        name = Your Name
        email = your_name@corporate_domain.com

[core]
        sshCommand = "ssh -i ~/.ssh/professional_key"

You can finally start contributing to the project now ✌️