What is SSH?
SSH (Secure Shell) is a protocol that lets you securely connect to remote computers and services—such as Git repositories—over the internet.
SSH uses a key pair (a public key and a private key) to ensure only you can access your remote resources.
Key SSH Concepts & Commands
How SSH Keys Work
- Your public key is like a lock—you share it with servers (e.g., GitHub, GitLab, Bitbucket).
- Your private key is like the actual key—you keep it safe and never share it.
- Only the matching private key can unlock what’s secured by the public key.
Generating an SSH Key Pair
To create a new SSH key pair, run this in your terminal (Linux, macOS, or Git Bash on Windows):
ssh-keygen -t rsa -b 4096 -C "your@email.com"
Follow the prompts to:
- Choose a file location (press Enter to use the default: ~/.ssh/id_rsa)
- Set a passphrase (optional but recommended)
Adding Your Key to the SSH Agent
Load your private key into the SSH agent so Git and other tools can use it:
ssh-add ~/.ssh/id_rsa
Copying Your Public Key
To add your public key to your Git hosting service, copy it using one of these commands:
macOS:
pbcopy < ~/.ssh/id_rsa.pub
Windows (Git Bash):
clip < ~/.ssh/id_rsa.pub
Linux:
cat ~/.ssh/id_rsa.pub
Then, paste the copied key into your account settings on GitHub, GitLab, or Bitbucket.
Listing & Removing Loaded SSH Keys
- List keys currently loaded:
ssh-add -l
- Remove a key from the agent:
ssh-add -d ~/.ssh/id_rsa
Troubleshooting SSH
1.If you see Permission denied:
- Confirm your public key is added to your Git host.
- Make sure your private key is loaded (ssh-add -l).
chmod 600 ~/.ssh/id_rsa
3.Debug with verbose output:
ssh -vT git@github.com
4.Ensure your Git remote URL starts with git@ (not https://).
