Multiple Git Account Setup (Ubuntu version)

ssh-add is a command for adding SSH private keys into the SSH authentication agent for implementing single sign-on with SSH. The agent process is called ssh-agent;

The cool thing about ssh-agent and ssh-add is that they allow the user to use any number of servers, spread across any number of organizations, without having to type in a password whenever moving between servers. This is commonly used by system administrators to move among the machine they administer. It is also widely used in universities and research institutions for accessing computing resources.

More paractical example would be: when anyone shift to new organization and get a new organization email address for the specific organization. He/She might need to create a VCS(version control system) account at github, bitbuckt, gitlab etc. Most Developer already have one personal account on any of the those VCS sites. So to setup this two account on a single machine sometime complex. In this post we will learn how to setup two or more VCS account on a single machine.

The below command will work on Ubuntu and Mac but Windows may not. But In windows, using window subsystem (WSL) will solved below command issue.

Step 1: Create ssh key for different email address

# With Office Email
ssh-keygen -t rsa -b 4096 -C "rezwanul.haque@vivasoftltd.com" -f rezwanul.viva

# With Personal Email
ssh-keygen -t rsa -b 4096 -C "rezwanul.cse@gmail.com" -f rezwanul-haque

add this ssh public keys to respective VCS accounts

Step 2: Create a config file on .ssh file

touch config

sudo vim config

Add this

# Personal account - default config
Host github.com-rezwanul-haque
        HostName github.com
        User git
        IdentityFile ~/.ssh/rezwanul-haque
# Work account - Viva
Host github.com-rezwanul-viva
        HostName github.com
        User git
        IdentityFile ~/.ssh/rezwanul.viva

Step 3: Create common ~/.gitconfig file at home directory

sudo vim ~/.gitconfig

Add this to ~/.gitconfig

# Default account-Personal
[user]
        name = rezwanul-haque
        email = rezwanul.cse@gmail.com
# Professional account-Office
[includeIf "gitdir:~/<office_work_space_path>/"]
        path = ~/<office_work_space_path>/.gitconfig-viva

Step 4: Create organization specific gitconfig to organization workspace folder

# Professional account-organization
[user]
    name = rezwanul-haque-viva
    email = rezwanul.haque@vivasoftltd.com

Step 5: remove ssh keys and entities from the SSH agent

ssh-add -D

Step 6: Add keys and entities

ssh-add rezwanul-haque
ssh-add rezwanul.viva

# Check if added or not
ssh-add -l

Step 7: Test with Connection using ssh

ssh -T github.com-rezwanul-haque
ssh -T github.com-rezwanul-viva

Also read this aricle on my personal gist

Step 8: Cloning any project with organization account(required)

# need to add github-hostname
git clone git@<HostName>:Rezwanul-Haque-Viva/<office_project_repo>.git

Example: git clone git@github.com-rezwanul-viva:Rezwanul-Haque-Viva/<office_project_repo>.git