Here are the steps to use multiple github accounts on same machine. Let's assume that we have 2 github accounts.

• github.com/mygit
• github.com/companygit

ssh-add -D

ssh-keygen -t rsa -C "id_rsa_mygit"
ssh-keygen -t rsa -C "id_rsa_companygit"

NOTE: Replace "id_rsa_mygit" and "id_rsa_companygit" with your own words. (e.g. ssh-keygen -t rsa -C "id_rsa_orkiv")

ssh-add ~/.ssh/id_rsa_mygit
ssh-add ~/.ssh/id_rsa_companygit

touch ~/.ssh/config

Open up ~/.ssh/config file with command-line editor. (e.g. sudo nano ~/.ssh/config)

Add the following configuration.

Host github.com-mygit
	HostName github.com
	User git
	IdentityFile ~/.ssh/id_rsa_mygit

Host github.com
	HostName github.com
	User git
	IdentityFile ~/.ssh/id_rsa_companygit

NOTE: For the 2nd account, the Host is github.com. Why?

When I use another name(e.g. Host github.com-companygit), the first Host(for mygit) was invoked for the other hosts and getting the following error.

ERROR: Permission to [companygit/test.git] denied to [mygit].
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

After changing the Host as github.com for the second account, the error was gone.