Setting Up GitHub SSH Keys on Linux

This guide explains how to generate and add SSH keys for GitHub authentication.

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1. Check for Existing SSH Keys

Run:

ls -l ~/.ssh/id_ed25519.pub

• If the file exists, skip to Step 3.
• If not found, move to Step 2.

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2. Generate a New SSH Key

Run:

ssh-keygen -t ed25519 -C "your_email@example.com"

• When prompted for a location, press ENTER to accept the default.
• When asked for a passphrase, press ENTER (or set a passphrase for security).

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3. Start and Add SSH Key to SSH Agent

Start the SSH agent:

eval "$(ssh-agent -s)"

Add your key:

ssh-add ~/.ssh/id_ed25519

Verify the key is added:

ssh-add -l

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4. Copy SSH Public Key

Show the key:

cat ~/.ssh/id_ed25519.pub

Copy the output (starting with ssh-ed25519).

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5. Add SSH Key to GitHub

1. Go to GitHub → Settings → SSH and GPG Keys:
   https://github.com/settings/keys
2. Click "New SSH Key".
3. Set a Title (e.g., "My Linux Machine").
4. Paste the copied SSH key.
5. Click "Add SSH Key".

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6. Test SSH Connection

Run:

ssh -T git@github.com

If successful, you should see:

Hi yourusername! You've successfully authenticated, but GitHub does not provide shell access.

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7. Use SSH for Git Operations

Check your GitHub remote URL:

git remote -v

If it uses HTTPS (https://github.com/...), change it to SSH:

git remote set-url origin git@github.com:yourusername/repository.git

Now, you can push and pull using SSH:

git push origin main
git pull origin main

GitHub SSH authentication is now set up!