Good if only you have access to host1 and host2, but they have no access to your host (so ncat won't work) and they have no direct access to each other.

ssh -X example.org xeyes The SSH server configuration requires: X11Forwarding yes # this is default in Debian And it's convenient too: Compression delayed

remove the host for the .ssh/know_host file

it compresses the files and folders to stdout, secure copies it to the server's stdin and runs tar there to extract the input and output to whatever destination using -C. if you emit "-C /destination", it will extract it to the home folder of the user, much like `scp file user@server:`. the "v" in the tar command can be removed for no verbosity.

Just run the command, type your password, and that's the last time you need to enter your password for that server. This assumes that the server supports publickey authentication. Also, the permissions on your home dir are 755, and the permissions on your .ssh dir are 700 (local and remote).

This can be much faster than downloading one or both trees to a common servers and comparing the files there. After, only those files could be copied down for deeper comparison if needed. Show Sample Output

Execute it from the source host, where the source files you wish backup resides. With the minus '-' the tar command deliver the compressed output to the standar output and, trough over the ssh session to the remote host. On the other hand the backup host will be receive the stream and read it from the standar input sending it to the /path/to/backup/backupfile.tar.bz2 Show Sample Output

When using tcpdump, specify -U option to prevent buffering.

This is also handy for taking a look at resource usage of a remote box. ssh -t remotebox top

If your firewall or proxy at your location prevents connection to a particular host or port, you can use ssh to tunnel to your home server and do it there instead.

This command will copy a folder tree (keeping the parent folders) through ssh. It will: - compress the data - stream the compressed data through ssh - decompress the data on the local folder This command will take no additional space on the host machine (no need to create compressed tar files, transfer it and then delete it on the host). There is some situations (like mirroring a remote machine) where you simply cant wait for a huge time taking scp command or cant compress the data to a tarball on the host because of file system space limitation, so this command can do the job quite well. This command performs very well mainly when a lot of data is involved in the process. If you copying a low amount of data, use scp instead (easier to type) Show Sample Output

Admittedly, I'd never have thought of this without the earlier examples, but here's one that you can execute from your workstation to just display the image from another, without separately doing a file transfer, etc. By the way, I hear a loud beep coming from the other room, so I guess it's not too stealthy :-D

This command will: 1. open an SSH tunnel to 2. go to background 3. wait for 10 seconds for the connection 4. during the 10 seconds wait it will localy run 'rdesktop' to connect to the remote host through the created SSH tunnel. Password-less log in can be achieved (when server allows it) by adding '-p ' to the 'rdesktop' command

Useful to move many files (thousands or millions files) over ssh. Faster than scp because this way you save a lot of tcp connection establishments (syn/ack packets). If using a fast lan (I have just tested gigabyte ethernet) it is faster to not compress the data so the command would be: tar -cf - /home/user/test | ssh user@sshServer 'cd /tmp; tar xf -'

connects to host via ssh and displays the live transfer speed, directing all transferred data to /dev/null needs pv installed Debian: 'apt-get install pv' Fedora: 'yum install pv' (may need the 'extras' repository enabled) Show Sample Output

Will return the SSH server key information for each host you have in your ~/.ssh/known_hosts file, including key size, key fingerprint, key IP address or domain name, and key type. Show Sample Output

Useful to get network access to a machine behind shared IP NAT. Assumes you have an accessible jump host and physical console or drac/ilo/lom etc access to run the command. Run the command on the host behind NAT then ssh connect to your jump host on port 2222. That connection to the jump host will be forwarded to the hidden machine. Note: Some older versions of ssh do not acknowledge the bind address (0.0.0.0 in the example) and will only listen on the loopback address.

standard image viewers do not seem to be able to open a FIFO file. xloadimage was the first one i've stumbled upon that can handle this. Show Sample Output

The important thing to note in this command, is the "-n" flag.

http://www.debian-administration.org/article/Running_multiple_X11_sessions

Source: http://unix.derkeiler.com/Newsgroups/comp.unix.shell/2008-04/msg00068.html