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SSH

Created August 18, 2024 · Updated March 11, 2026 · 1 min read · 215 words

Section titled “Link”

https://www.openssh.com/

Notes

Section titled “Notes”

The Secure Shell Protocol (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network.[2] Its most notable applications are remote login and command-line execution.

Source: Wikipedia

FAQ

Section titled “FAQ”

Download a directory from a SSH server into an archive

Section titled “Download a directory from a SSH server into an archive”
Terminal window
scp -r username@hostname:/path/from/remote /path/to/local

Source: StackOverflow

Could not load host key: /etc/ssh/ssh_host_ed25519_key

Section titled “Could not load host key: /etc/ssh/ssh_host_ed25519_key”

If you’re getting this error message in the log file, you most likely have the ed25519 HostKey enabled in your sshd_config file but for some reason, no host key was generated for it.

Since openssh-6.4 you can run the ssh-keygen command to generate any missing host keys:

Terminal window
  ssh-keygen -A

Source: https://trick77.com/could-not-load-host-key-etcsshssh_host_ed25519_key/

Starting OpenSSH client from Python

Section titled “Starting OpenSSH client from Python”
 subprocess.call([
  "ssh", # Path to ssh
  "-i", # Use private key file
  "~/.ssh/id_rsa", # Path to private key
  "user@hostname" # Host and username to connect with
])

Changing the comment field of an RSA key

Section titled “Changing the comment field of an RSA key”

All I had to do was

Terminal window
ssh-keygen -c -C "my new comment" -f ~/.ssh/my_ssh_key

Source: SuperUser

Switching directory automatically after connecting with SSH

Section titled “Switching directory automatically after connecting with SSH”

Add an entry in the local SSH config:

Host SOME_HOSTNAME
  RemoteCommand cd DESIRED_DIRECTORY ; /usr/bin/env bash
  RequestTTY yes

Agent forwarding on a connection basis

Section titled “Agent forwarding on a connection basis”
Terminal window
ssh -A user@host

Use local aliases on SSH servers

Section titled “Use local aliases on SSH servers”

See Gemini conversation

Resources

Section titled “Resources”