How to copy an SSH key to a new Linux machine

Published on 22 July, 2026

If you keep your SSH key pair in a password manager rather than backing up the files directly, you need to manually recreate the key files whenever you set up a new Linux machine. I do this often enough after reformats that I decided to write it down for future me.

1. Create the .ssh directory

# Create the directory
mkdir -p ~/.ssh

# Set the correct permissions
chmod 700 ~/.ssh

2. Create the key files and paste in the keys

Create the private and public keys, pasting in the matching key content from your password manager. Make sure there's no extra blank line or trailing whitespace, then save and exit in nano.

(Swap id_ed25519 for id_rsa etc. if you use a different key type.)

# Create the private key
nano ~/.ssh/id_ed25519

# Create the public key
nano ~/.ssh/id_ed25519.pub

3. Set the correct permissions

Set the correct permissions for each key:

chmod 600 ~/.ssh/id_ed25519
chmod 644 ~/.ssh/id_ed25519.pub

Verify with:

ls -la ~/.ssh

You should see:

drwx------  ...  .
-rw-------  ...  id_ed25519
-rw-r--r--  ...  id_ed25519.pub

SSH will refuse to use the key if these permissions aren't set correctly, usually with an "UNPROTECTED PRIVATE KEY FILE" error.

4. Test the key

ssh-add ~/.ssh/id_ed25519

If this succeeds, the key is loaded and ready to use with GitHub or any server that already trusts it.

Closing thoughts

This is the whole process. No need to regenerate a new key pair and update it everywhere just because you reformatted a machine. Keep the key pair in your password manager, and these four steps are all you need on the next fresh install.

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