An example of using a specific ssh key for a given host

host-specific-ssh-key.md

Generate a dedicated SSH key

SSH key creation

ssh-keygen -t rsa -b 4096 -f ~/.ssh/id-rsa-github -C "github.com"
chmod 600 ~/.ssh/id-rsa-github

Edit ~/.ssh/config:

Host github.com
  Hostname github.com
  User $__SSH_USER__$$
  IdentityFile ~/.ssh/id-rsa-github

Test SSH key

ssh -vT [email protected]

Reset passphrase

ssh-keygen -f ~/.ssh/id-rsa-github -p