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Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.
Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):
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This will output the sound from your microphone port to the ssh target computer's speaker port. The sound quality is very bad, so you will hear a lot of hissing.
Useful for checking if there are differences between local and remote files.
Unreachable_host is unavailable from local network, but it's available from reachable_host's network. This command creates a connection to unreachable_host through "hidden" connection to reachable_host.
If you use Mac OS X or some other *nix variant that doesn't come with ssh-copy-id, this one-liner will allow you to add your public key to a remote machine so you can subsequently ssh to that machine without a password.
Create a persistent SSH connection to the host in the background. Combine this with settings in your ~/.ssh/config:
All the SSH connections to the machine will then go through the persisten SSH socket. This is very useful if you are using SSH to synchronize files (using rsync/sftp/cvs/svn) on a regular basis because it won't create a new socket each time to open an ssh connection.
In this case it's better do to use the dedicated tool
Directly attach a remote screen session (saves a useless parent bash process)
Of course you need to be able to access host A for this ;-)
Shorter, easier to remember version of cmd#7636
NTP is better, but there are situations where it can't be used. In those cases, you can do this to sync the local time to a server.
Knock on ports to open a port to a service (ssh for example) and knock again to close the port. You have to install knockd.
See example config file below.
logfile = /var/log/knockd.log
sequence = 3000,4000,5000
seq_timeout = 5
command = /sbin/iptables -A INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT
tcpflags = syn
sequence = 5000,4000,3000
seq_timeout = 5
command = /sbin/iptables -D INPUT -i eth0 -s %IP% -p tcp --dport 22 -j ACCEPT
tcpflags = syn
Much simpler method. More portable version: ssh host -l user "`cat cmd.txt`"
This captures traffic on a remote machine with tshark, sends the raw pcap data over the ssh link, and displays it in wireshark. Hitting ctrl+C will stop the capture and unfortunately close your wireshark window. This can be worked-around by passing -c # to tshark to only capture a certain # of packets, or redirecting the data through a named pipe rather than piping directly from ssh to wireshark. I recommend filtering as much as you can in the tshark command to conserve bandwidth. tshark can be replaced with tcpdump thusly:
ssh [email protected] tcpdump -w - 'port !22' | wireshark -k -i -
Dumps a MySQL database over a compressed SSH tunnel and uses it as input to mysql - i think that is the fastest and best way to migrate a DB to a new server!
Even faster without the need for cut... :)
Long before tabbed terminals existed, people have been using Gnu screen to open many shells in a single text terminal. Combined with ssh, it gives you the ability to have many open shells with a single remote connection using the above options. If you detach with "Ctrl-a d" or if the ssh session is accidentally terminated, all processes running in your remote shells remain undisturbed, ready for you to reconnect. Other useful screen commands are "Ctrl-a c" (open new shell) and "Ctrl-a a" (alternate between shells). Read this quick reference for more screen commands: http://aperiodic.net/screen/quick_reference
(also works on Ubuntu) Copies the 'install,' 'hold,' 'deinstall' and 'purge' states of packages on the remote machine to be matched on the local machine. Note: if packages were installed on the local machine that were never installed on the remote machine, they will not be deinstalled by this operation.
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)
It can resume a failed secure copy ( usefull when you transfer big files like db dumps through vpn ) using rsync.
It requires rsync installed in both hosts.
rsync --partial --progress --rsh=ssh $file_source $user@$host:$destination_file local -> remote
rsync --partial --progress --rsh=ssh $user@$host:$remote_file $destination_file remote -> local
1. SSH into a machine
2. Tunnels VNC port to your local computer ("-L 5900:localhost:5900")
3. Runs a single use vnc server ("x11vnc -safer -localhost -nopw -once -display :0")
4. Goes into the background ("-f")
5. Runs VNC viewer on the local computer connecting to the remote machine via the newly created SSH tunnel ("vinagre localhost:5900")