How to Connect and use multiple github account on Single Deveice?

1️⃣ Introduction: Why Multiple GitHub Accounts Exist

Many developers have:

• 👤 Personal GitHub account

• 🏢 Company GitHub account

• 🧑‍💻 Client / Freelance GitHub account

GitHub allows this.
Your computer, however, needs to be taught how to switch between them safely.

That is exactly what this guide does.

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2️⃣ How GitHub Knows “Who You Are”

There are two ways GitHub identifies you:

❌ Password / HTTPS (Not recommended)

• Asks for login repeatedly

• Breaks with multiple accounts

• Easy to misconfigure

✅ SSH (Recommended & professional)

• Uses cryptographic keys

• No passwords

• Works perfectly with multiple accounts

👉 We will use SSH only.

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3️⃣ What Is SSH? (Simple Explanation)

Think of SSH like a house key:

• 🗝️ Private key → stays on your computer

• 🧾 Public key → given to GitHub

When GitHub sees your key:

“Yes, I recognize this person.”

Each GitHub account gets its own key.

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4️⃣ How Multiple Accounts Work on One Computer

Your computer:

• Stores multiple SSH keys

• Uses a map (config file) to decide which key to use

• Automatically picks the correct identity per project

📌 You never log in and out manually.

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5️⃣ Preparing Your System

✅ Windows

• Install Git for Windows

• Use PowerShell or Git Bash

• SSH is already included

✅ Ubuntu / Linux

sudo apt update
sudo apt install git openssh-client

Verify:

git --version
ssh -V

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6️⃣ Creating SSH Keys (Most Important Step)

One account = one key

Never reuse keys.

🔹 Windows & Ubuntu (same command)

ssh-keygen -t ed25519 -C "personal@email.com"

Press Enter to accept default location.

Repeat for second account:

ssh-keygen -t ed25519 -C "work@email.com"

Rename keys when asked:

id_ed25519_personal
id_ed25519_work

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7️⃣ Adding Keys to GitHub

For each account:

1. GitHub → Settings → SSH & GPG Keys

2. Click New SSH Key

3. Copy the .pub file content:

    cat ~/.ssh/id_ed25519_personal.pub
   

4. Paste → Save

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8️⃣ Teaching Your Computer Which Key to Use

Create config file:

~/.ssh/config

Add:

# Personal account
Host github-personal
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_ed25519_personal

# Work account
Host github-work
  HostName github.com
  User git
  IdentityFile ~/.ssh/id_ed25519_work

🧠 This is the secret sauce.

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9️⃣ Using Repositories (Real Example)

Personal repo:

git clone git@github-personal:username/repo.git

Work repo:

git clone git@github-work:company/repo.git

Git now:

• Uses the correct key

• Uses the correct GitHub account

• Never mixes identities

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🔍 Mini Case Study

Scenario:
Zia works at a company and freelances at night.

• Company laptop → work GitHub

• Same laptop → personal projects

Using SSH config:
✅ No login issues
✅ No permission errors
✅ No accidental pushes to wrong account

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⚠️ Common Beginner Mistakes

❌ Using HTTPS + SSH together
❌ One SSH key for all accounts
❌ Wrong key permissions
❌ Forcing wrong key path

✅ This guide avoids all of them.

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🌟 Best Practices (Professional Level)

• One key per account

• Clear key names

• Backup .ssh folder securely

• Never share private keys

• Use SSH config always

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🛠️ Quick Troubleshooting Checklist

ssh-add -l
ssh -T git@github.com
git remote -v

If SSH works but Git fails → wrong key mapping.