This is how I currently manage multiple SSH keys for Github on a single computer. Thanks to this gist for giving me the idea to look into this.
Creating an SSH key
On Windows 10 using Git Bash, navigate to the ~/.ssh folder, using cd ~/.ssh. If this folder doesn’t exist, create it using mkdir ~/.ssh.
Github recommends (as of writing) running this command to create an SSH key (make sure to replace this example email with your own):
$ ssh-keygen -t ed25519 -C "your_email@example.com"
Give a name to your key, optionally give it a password then the key will be generated.
You can add your key by first running this command to start the SSH agent:
$ eval $(ssh-agent)
Then add your key (the one without the .pub) to this Git Bash session using:
$ ssh-add ~/.ssh/your_key
Then add the .pub version of the key to Github.
Auto adding an SSH key when Git Bash starts
Adding an SSH key only works for that session, once you close and reopen Git Bash you’ll need to add it again.
If you want the SSH key to automatically be added each time Git Bash is opened, on Windows 10 open your .bash_profile file. From Git Bash you can open this by running start ~/.bash_profile. If that doesn’t work, open the folder it’s in by running start ~.
Then add this to your .bash_profile and it should run each time Git Bash is opened:
eval $(ssh-agent)
ssh-add ~/.ssh/your_key # replace with your own key
Managing multiple SSH keys
If you have more than one Github account with different SSH keys for each, you might instead need to pick which one you want each time Git Bash runs. In this case, you can add the SSH code inside a function in .bash_profile:
function ssh-add-custom {
eval $(ssh-agent)
ssh-add ~/.ssh/your_key # replace with your own key
}
function ssh-add-custom-two {
eval $(ssh-agent)
ssh-add ~/.ssh/your_key_2 # replace with your own key
}
In the above example, you can add either SSH key to your current session by typing ssh-add-custom or ssh-add-custom-two in Git Bash, depending on which you need.