ssh

SSH Skill

This skill provides capabilities for establishing and managing SSH connections to remote machines. Windows PowerShell equivalents for SSH config creation, key paths, ssh-agent, and permissions are in references/windows.md.

Capabilities

• Establish SSH connections using password or key-based authentication
• Generate and manage SSH key pairs
• Configure SSH for easier connections
• Execute commands on remote machines
• Transfer files between local and remote machines
• Manage SSH configurations and known hosts

Authentication Methods

Password Authentication

ssh username@hostname

When prompted, you should ask the user for their password or a private key.

Key-Based Authentication

Generate a new SSH key pair:

ssh-keygen -t ed25519 -f ~/.ssh/key_name -C "comment" -N ""

Copy the public key to the remote server:

ssh-copy-id -i ~/.ssh/key_name.pub username@hostname

Connect using the private key:

ssh -i ~/.ssh/key_name username@hostname

SSH Configuration

Create or edit the SSH config file for easier connections:

mkdir -p ~/.ssh
cat > ~/.ssh/config << 'EOF'
Host alias
    HostName hostname_or_ip
    User username
    IdentityFile ~/.ssh/key_name
    Port 22
    ServerAliveInterval 60
EOF
chmod 600 ~/.ssh/config

Then connect using the alias:

ssh alias

Common SSH Options

• -p PORT: Connect to a specific port
• -X: Enable X11 forwarding
• -L local_port:remote_host:remote_port: Set up local port forwarding
• -R remote_port:local_host:local_port: Set up remote port forwarding
• -N: Do not execute a remote command (useful for port forwarding)
• -f: Run in background
• -v: Verbose mode (add more v's for increased verbosity)

File Transfer with SCP

Copy a file to the remote server:

scp /path/to/local/file username@hostname:/path/to/remote/directory/

Copy a file from the remote server:

scp username@hostname:/path/to/remote/file /path/to/local/directory/