Compress a file before scp from remote server to local

ssh user@host "tar -zcvf - -C /path/to/dir filename" | tar -zxvf -

Note: only use when it's much faster to transfer a compressed file to your machine than transferring the original one.

Credits:
https://superuser.com/a/1354868
https://stackoverflow.com/a/3035446/1032449

SSHFS - Mount remote directory through gateway machine

1. Expose target target server ssh port with ssh local port forwarding
   $ ssh -C -N -L localhost:local_port:target:target_ssh_port gateway_user@gateway
2. Mount with sshfs through the port just exposed
   $ sshfs target_user@localhost:/target_directory /mount_point -o port=local_port

Example:

$ ssh -C -N -L localhost:22222:tap-machine:22 tapvpn@company-vpn-host.org

$ sshfs tap@localhost:~/work /mnt/work -o port=22222

Credit: Mounting Filesystems with SSH Forwarding Across a Gateway

[Solved] Could not open a connection to your authentication agent.

Run this command

eval `ssh-agent`

Credit:  http://www.worldofnubcraft.com/1926/could-not-open-a-connection-to-your-authentication-agent-ssh-add-error/

Disable SSH host key checking

I summarized this from Linux Commando: How to disable SSH host key checking

He suggested 3 approaches

1. $ sed -i 3d ~/.ssh/known_hosts
2. Use parameters
   * StrictHostKeyCheckin
   * UserKnownHostsFile
   

   ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no username@hostname

3. Config file ~/.ssh/config (or /etc/ssh/ssh_config for global) & restart ssh
   

   Host 192.168.0.*
   StrictHostKeyChecking no
   UserKnownHostsFile=/dev/null