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How to Use ssh-copy-id to Copy Your SSH Key to a Server
ssh-copy-id adds your public key to a server in one command, so you can log in without a password. Here’s how to use it, its most useful options, what to do on Windows where it isn’t included, and how to fix common errors.
Mac & LinuxWindows alternativeCustom ports & keysTroubleshooting
The basics
Copy your key in one command
ssh-copy-id user@203.0.113.10Enter the account’s password one last time. ssh-copy-id logs in, adds your public key to ~/.ssh/authorized_keys on the server, and sets the right permissions. Then test it with ssh user@203.0.113.10; you won’t be asked for a password.
No SSH key yet?
ssh-copy-id copies an existing key, so create one first with ssh-keygen -t ed25519. Our guide on how to generate an SSH key walks through it on every operating system.
Options
Useful ssh-copy-id options
Copy a specific key (-i)
ssh-copy-id -i ~/.ssh/id_ed25519.pub user@serverUse a custom SSH port (-p)
ssh-copy-id -p 2222 user@serverSee what would be copied (-n, dry run)
ssh-copy-id -n user@serverCopy even if it looks installed (-f)
ssh-copy-id -f -i ~/.ssh/id_ed25519.pub user@serverWithout -i, ssh-copy-id copies the keys loaded in your ssh-agent, or your newest key in ~/.ssh. Using -i is the safest way to know exactly which key goes to the server.
Windows
ssh-copy-id on Windows
Windows includes the OpenSSH client but not ssh-copy-id. This PowerShell one-liner does the same job: it creates the .ssh folder on the server if needed, adds your key and sets the permissions.
Prefer a graphical app? PuTTY users can paste the key into authorized_keys by hand, as shown below.
PowerShell equivalent of ssh-copy-id
type $env:USERPROFILE\.ssh\id_ed25519.pub | ssh user@server "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys"Manual method
Add your key without ssh-copy-id
Copy your public key
Show it with cat ~/.ssh/id_ed25519.pub and copy the whole line.
Log in to the server
Connect with your password, or use your host’s web console.
Add the key
Run mkdir -p ~/.ssh && nano ~/.ssh/authorized_keys, paste the key on its own line and save.
Fix permissions
Run chmod 700 ~/.ssh && chmod 600 ~/.ssh/authorized_keys.
Setting up a brand-new server? Most hosts, including DigitalOcean and Hostinger, let you paste your public key when you create the server, so you can skip this step entirely.
Troubleshooting
ssh-copy-id errors and fixes
| Message | Fix |
|---|---|
ERROR: No identities found | You don’t have a key yet, or it isn’t in the default place. Create one with ssh-keygen -t ed25519, or point to it with -i. |
ssh-copy-id: command not found | On Windows, use the PowerShell command above. On a Mac without it, install it with brew install ssh-copy-id. |
Permission denied (publickey) | The server already refuses passwords, so ssh-copy-id can’t log in. Add the key through your host’s web console or dashboard instead. |
All keys were skipped because they already exist | The key is already on the server. If login still fails, check the username and the file permissions on the server. |
| Still asked for a password afterwards | Make sure you connect as the same user you copied the key to, and run ssh -v to see whether the key is offered. |
Next step
Now turn off password logins
Once key login works, disable passwords on the server so bots can’t guess their way in. Test from a second terminal before closing your current session. Our SSH hardening guide has the exact settings.
Disable passwords
echo "PasswordAuthentication no" | sudo tee /etc/ssh/sshd_config.d/00-hardening.conf
sudo sshd -t && sudo systemctl restart sshNeed a server?
Need a server to copy your key to?
Most hosts below let you paste your public key when you create the server, so you may not even need ssh-copy-id.
DigitalOcean
Simple cloud servers with great docs. Add your SSH key when you create a Droplet.
From about $4/month
View DigitalOcean dealsHostinger
4 GB of RAM and NVMe storage on the entry VPS plan, with an easy control panel.
About $5.19/month on a 24-month term with our extra 20% off
Get 20% off Hostinger VPSYearly KVM VPS deals for about the price of one month elsewhere. Great for learning.
From about $11/year on promo
View RackNerd dealsPrices are approximate. Compare all VPS hosts, including Vultr and ShockHosting.
FAQ
ssh-copy-id questions, answered
What does ssh-copy-id actually do?
It logs in to the server with your password, appends your public key to ~/.ssh/authorized_keys for that user, and makes sure the .ssh folder and file have safe permissions. It never copies your private key.
Does ssh-copy-id copy my private key?
No. It only copies the public key, the .pub file. Your private key never leaves your computer.
Can I run ssh-copy-id more than once?
Yes. It checks whether the key is already installed and skips it, so running it again is harmless. Use -f to force it anyway.
How do I copy a key for a different user?
Put that username in the command, for example ssh-copy-id deploy@server. The key is added to that user’s authorized_keys file, and you will need that user’s password once.
How do I remove a key that ssh-copy-id added?
Log in to the server, open ~/.ssh/authorized_keys in a text editor and delete the line that ends with your key’s comment, then save the file.
Does ssh-copy-id work with a custom port?
Yes. Add -p and the port number, for example ssh-copy-id -p 2222 user@server, or set the port for that host in your SSH config file.
Need a server to copy your key to?
Set up a new Linux VPS the right way, with your SSH key added from the start, in about 30 minutes.