Managing SSH Sessions: Essential Commands and Tips

How to Safely Exit a Stuck SSH Session

Step 1: Press Enter

• Description: Ensures you are at the beginning of a new line, necessary for the commands to be recognized.
• Usage: Hit the Enter key.

Step 2: Type ~

• Description: Uses the tilde key as a special escape sequence initiator for SSH.
• Usage: Type the tilde key ~.

Step 3: Type .

• Description: Completes the escape sequence to terminate the connection.
• Usage: Type the dot ..

Basic SSH Client Commands

Terminate the session: ~.

• Description: Close the current SSH connection, especially useful when the session is stuck or unresponsive.
• Usage: Simply type ~. on a new line in your SSH session.

Suspend the SSH session: ~^Z or ~CTRL+Z

• Description: Suspends your SSH session, allowing you to return to your local shell without disconnecting.
• Usage: Type ~^Z or ~CTRL+Z. Use fg to resume the session.

Send the session to the background: ~&

• Description: Sends the current SSH session to the background immediately, combining the steps of suspending and then backgrounding the session.
• Usage: Type ~& after suspending the session.

Display the help menu: ~?

• Description: Displays a list of all supported escape sequences, providing a quick reference.
• Usage: Type ~? to see the help menu.

Check the connection status: ~#

• Description: Shows information about the current SSH tunnel and forwarded connections, useful for debugging or checking the status of port forwarding.
• Usage: Type ~# during your SSH session.

Forward a port: ~C

• Description: Opens a command line to add port forwarding rules dynamically during an active SSH session.
• Usage: Type ~C and then enter the port forwarding rule.

Advanced Usage

Escape character for literal ~: ~~

• Description: Allows you to send a literal ~ at the beginning of a line, useful when ~ is part of a command or data.
• Usage: Type ~~ when needed.

Verbose mode

• Description: Provides verbose output with detailed debug messages about the connection setup and process, invaluable for troubleshooting.
• Usage: Start SSH with the -v flag, e.g., ssh -v user@host.

Tips for Effective SSH Use

• Customizing SSH configurations: Create custom configurations for each host in the ~/.ssh/config file, including usernames, identities, port numbers, and more.
• Using key-based authentication: Enhance security and convenience by using SSH keys instead of passwords, using public-private key cryptography for authentication.
• Multiplexing connections: Utilize SSH's support for connection multiplexing to speed up subsequent connections by reusing a single connection.