Multiple SSH keys for different github accounts

multiple_ssh_setting.md

Multiple SSH Keys settings for different git account

Create different public keys

Create different ssh keys for each git account

$ ssh-keygen -t rsa -b 4096 -N "" -C "$USER@$HOSTNAME to [email protected]" -f ~/.ssh/[email protected]_id_rsa
$ ssh-keygen -t rsa -b 4096 -N "" -C "$USER@$HOSTNAME to [email protected]" -f ~/.ssh/[email protected]_id_rsa
$ ssh-keygen -t rsa -b 4096 -N "" -C "$USER@$HOSTNAME to [email protected]" -f ~/.ssh/[email protected]_id_rsa
$ ssh-keygen -t rsa -b 4096 -N "" -C "$USER@$HOSTNAME to [email protected]" -f ~/.ssh/[email protected]_id_rsa

If you would like to use a passphrase then remove -N "" from the command, you will then be prompted for you pass-phrase.

This will create the following files

~/.ssh/[email protected]_id_rsa
~/.ssh/[email protected]_id_rsa
~/.ssh/[email protected]_id_rsa
~/.ssh/[email protected]_id_rsa

Please refer to github ssh issues for common problems.

You can add your keys to memory (give to ssh-agent) using the ssh-add command,

# run agent if it is'nt already 
$ eval `ssh-agent -s`

$ ssh-add ~/.ssh/[email protected]_id_rsa
$ ssh-add ~/.ssh/[email protected]_id_rsa
$ ssh-add ~/.ssh/[email protected]_id_rsa
$ ssh-add ~/.ssh/[email protected]_id_rsa

or modify ~/.ssh/config to specify that keys should be automatically added to a running ssh-agent

To list your added keys

$ ssh-add -l

to delete all cached keys with

$ ssh-add -D

Modify the ssh config

Make sure ~/.ssh exists and is writable

$ mkdir -p $HOME/.ssh
$ chmod 0700 $HOME/.ssh

Make sure ~/.ssh/config exists and open in your text editor (subl)

$ cd ~/.ssh/
$ touch config
$ subl -a config

Then add the following

#Set Git User Domains
Host *-github.com *-bitbucket.org *-bitbucket.com
  User git

#IdentityFile
Host tarranjones-*
  IdentityFile ~/.ssh/tarranjones@%h_id_rsa

Host otherusername-*
  IdentityFile ~/.ssh/otherusername@%h_id_rsa

#Hostnames
Host *-github.com
  Hostname github.com

Host *-bitbucket.com *-bitbucket.org
  Hostname bitbucket.org

Host *
  Protocol 2
  UseKeychain yes
  AddKeysToAgent yes
  IdentitiesOnly yes

Modify your Git config

I recommend setting your global config to match your most frequently used account details

$ git config --global user.name "tarranjones"
$ git config --global user.email "[email protected]"

Having the same username and email address for all your primary accounts across different git hosting providers is something worth thinking about. Your user config would have to be changed a lot less.

Clone you repo and modify your Git config

clone your repo

git clone tarranjones-github.com:username/repo.git

...or for an existing working directory

git remote set-url origin tarranjones-github.com:username/repo.git

you should set your user config for repositories where details differ from your global config details.

cd repo and modify git config

$ git config user.name "otherusername"
$ git config user.email "[email protected]"

then use normal flow to push your code

$ git add .
$ git commit -m "your comments"
$ git push

Heres a little helper function

usage: ssh [user@]host]
function ssh_keygen(){
    ssh-keygen -t rsa -b 4096 -N "" -C "$USER@$HOSTNAME to $1" -f ~/.ssh/"$1_id_rsa"
}

$ ssh_keygen [email protected]



further reading
alias to switch user.email http://stackoverflow.com/a/33079036/2273611

Another related article in Chinese

1. http://4simple.github.com/docs/multipleSSHkeys/