Here are step-by-step instructions for configuring and managing multiple GitHub accounts on a single computer, including SSH key setup and Git configuration:

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Step 1: Generate SSH Keys for Each GitHub Account

  1. Open your terminal.
  2. Generate a new SSH key for the first GitHub account: 
    ssh-keygen -t rsa -b 4096 -C "your_email_first_account@example.com"
    When prompted, save the key with a unique name, e.g., id_rsa_first_account.
  3. Generate a new SSH key for the second GitHub account: 
    ssh-keygen -t rsa -b 4096 -C "your_email_second_account@example.com"
    When prompted, save the key with a unique name, e.g., id_rsa_second_account.

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Step 2: Add SSH Keys to the SSH Agent

  1. Start the SSH agent in the background: 
    eval "$(ssh-agent -s)"
  2. Add the first SSH key to the SSH agent: 
    ssh-add ~/.ssh/id_rsa_first_account
  3. Add the second SSH key to the SSH agent: 
    ssh-add ~/.ssh/id_rsa_second_account

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Step 3: Add SSH Keys to GitHub Accounts

  1. Copy the SSH key for the first account to your clipboard: 
    pbcopy < ~/.ssh/id_rsa_first_account.pub
    If pbcopy is not available, you can use: 
    cat ~/.ssh/id_rsa_first_account.pub
  2. Log in to your first GitHub account and navigate to Settings > SSH and GPG keys > New SSH key. Paste the key and save.
  3. Repeat the process for the second account: 
    pbcopy < ~/.ssh/id_rsa_second_account.pub
    If pbcopy is not available, you can use: 
    cat ~/.ssh/id_rsa_second_account.pub
  4. Log in to your second GitHub account and navigate to Settings > SSH and GPG keys > New SSH key. Paste the key and save.

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Step 4: Configure SSH to Manage Multiple Accounts

  1. Edit the SSH config file: 
    nano ~/.ssh/config
  2. Add the following configurations: 
    # First GitHub account
Host github-first
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_rsa_first_account

# Second GitHub account
Host github-second
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_rsa_second_account

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Step 5: Configure Git for Multiple Accounts

  1. Set global Git configuration (if not already set): 
    git config --global user.name "Your Name"
git config --global user.email "your_email@example.com"
  2. For repositories associated with the first account, set the local Git configuration: 
    cd path/to/your/repository
git config user.name "Your Name for First Account"
git config user.email "your_email_first_account@example.com"
  3. For repositories associated with the second account, set the local Git configuration: 
    cd path/to/your/other/repository
git config user.name "Your Name for Second Account"
git config user.email "your_email_second_account@example.com"

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Step 6: Clone Repositories Using the Correct SSH Host

  1. For the first GitHub account, use: 
    git clone git@github-first:username/repository.git
  2. For the second GitHub account, use: 
    git clone git@github-second:username/repository.git

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Step 7: Push and Pull Using the Correct SSH Host

Git will automatically use the correct SSH key based on the configuration in the ~/.ssh/config file. That’s it! You have now configured and can manage multiple GitHub accounts on a single computer.