Commands tagged Network (129)

  • curl -> IP Adress curl -> Remote Host curl ->User Agent curl -> Port thonks to

    aajjk · 2010-04-21 13:10:33 35
  • Waiting for your server to finish rebooting? Issue the command above and you will hear a beep when it comes online. The -i 60 flag tells ping to wait for 60 seconds between ping, putting less strain on your system. Vary it to your need. The -a flag tells ping to include an audible bell in the output when a package is received (that is, when your server comes online).

    ping -i 60 -a IP_address
    haivu · 2009-03-04 06:21:22 13

  • 100
    lsof -i
    hank · 2009-04-25 14:24:04 9
  • Redirect the local port 2000 to the remote port 3000. The same but UDP: nc -u -l -p 2000 -c "nc -u 3000" It may be used to "convert" TCP client to UDP server (or viceversa): nc -l -p 2000 -c "nc -u 3000"

    nc -l -p 2000 -c "nc 3000"
    prayer · 2009-03-01 21:28:39 5
  • this command will send a message to the socket 25 on host in tcp. works on udp and icmp understand only IP address, not hostname. on the other side (, you can listen to this socket and test if you receive the message. easy to diagnose a firewall problem or not.

    echo "foo" > /dev/tcp/
    mobidyc · 2009-09-12 16:48:05 7
  • Yeah I know it's been up here a million times, but this service is a really clean and nice one. Nothing but your IP address on it. Actually I was to write something like this, and noticed this on appspot... ;) Show Sample Output

    ktoso · 2009-10-31 21:11:10 6
  • Works on any machine with nmap installed. Previous version does not work on machines without "seq". Also works on subnets of any size. Show Sample Output

    nmap -sP
    sdadh01 · 2010-06-05 14:48:37 2

  • 20
    sudo tcpdump -i wlan0 -n ip | awk '{ print gensub(/(.*)\..*/,"\\1","g",$3), $4, gensub(/(.*)\..*/,"\\1","g",$5) }' | awk -F " > " '{print $1"\n"$2}'
    tweet78 · 2014-04-11 22:41:32 1
  • Where < target > may be a single IP, a hostname or a subnet -sS TCP SYN scanning (also known as half-open, or stealth scanning) -P0 option allows you to switch off ICMP pings. -sV option enables version detection -O flag attempt to identify the remote operating system Other option: -A option enables both OS fingerprinting and version detection -v use -v twice for more verbosity. nmap -sS -P0 -A -v < target >

    nmap -sS -P0 -sV -O <target>
    starchox · 2009-02-18 07:32:03 6
  • Just a simple way without the need of additional tools. Of course, replace eth0 with your IF. Show Sample Output

    while [ /bin/true ]; do OLD=$NEW; NEW=`cat /proc/net/dev | grep eth0 | tr -s ' ' | cut -d' ' -f "3 11"`; echo $NEW $OLD | awk '{printf("\rin: % 9.2g\t\tout: % 9.2g", ($1-$3)/1024, ($2-$4)/1024)}'; sleep 1; done
    hons · 2011-03-22 10:02:23 3
  • works on Linux and Solaris. I think it will work on nearly all *nix-es Show Sample Output

    ifconfig -a | perl -nle'/(\d+\.\d+\.\d+\.\d+)/ && print $1'
    sneaker · 2009-07-31 09:49:17 4
  • Get all the networking related commands for your distro Show Sample Output

    apropos network |more
    shaiss · 2009-09-25 15:05:33 5
  • Curl is not installed by default on many common distros anymore. wget always is :) wget -qO-

    wget -qO-
    SuperJediWombat · 2010-06-24 03:49:14 4

  • 11
    dpoblador · 2010-10-09 08:12:26 0
  • The report mode of mtr produces a text formated result of the mtr run using the number of ping cycles stated by the command. This text file could then be attached to an email with ease. I use this also without the ">" portion when writing email from within mutt using VI from the command mode with ":r !mtr --report --report-cycles 10 Show Sample Output

    mtr --report --report-cycles 10 > google_net_report.txt
    CafeNinja · 2009-04-10 07:57:44 2

  • 9
    curl -s '' | sed 's/.*Current IP Address: \([0-9\.]*\).*/\1/g'
    kulor · 2009-08-06 11:54:31 4
  • Gets all kind of info, rocks ... for just the ip addess you can use or Show Sample Output

    pykler · 2012-05-16 18:22:28 4

  • 8
    nc -l -p 2000 < song.mp3
    prayer · 2009-03-02 15:54:21 4
  • On the machine acting like a server, run: iperf -s On the machine acting like a client, run: iperf -c where is the ip or hostname of the server. Show Sample Output

    iperf -s
    forcefsck · 2011-01-24 07:58:38 4
  • Trickle is a voluntary, cooperative bandwidth shaper. it works entirely in userland and is very easy to use. The most simple application is to limit the bandwidth usage of programs.

    trickle -d 60 wget http://very.big/file
    point_to_null · 2010-03-29 06:55:30 0
  • I'd rather this one on Gnome, as I'm used to be listening some music while working. I've even created a bash function which receives ADDRESS as parameter.

    until ping -c1 ADDRESS;do true;done;zenity --warning --text "ADDRESS is back"
    marcusrp · 2011-09-26 18:51:38 3
  • Replace 500ms by the desired delay. To remove it: sudo tc qdisc del dev lo root netem delay 500ms

    sudo tc qdisc add dev lo root netem delay 500ms
    caiosba · 2012-11-05 05:29:51 0
  • It finds, specifically, the connections to the HTTP and HTTPS ports as source ports. You can check for destination ports as well. Show Sample Output

    ss -o state established '( dport = :http or sport = :https )'
    renich · 2019-08-14 17:28:13 11
  • To connect to the shell run: nc 2000

    nc -l -p 2000 -e /bin/bash
    prayer · 2009-03-02 15:58:25 4

  • 5
    mii-tool [if]
    raphink · 2009-02-25 23:55:00 1
  •  1 2 3 >  Last ›

What's this? is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Check These Out

Watch the progress of 'dd'
The 'dd' command doesn't provide a progress when writing data. So, sending the "USR1" signal to the process will spit out its progress as it writes data. This command is superior to others on the site, as it doesn't require you to previously know the PID of the dd command.

Download Youtube video with wget!
Nothing special required, just wget, sed & tr!

Find if the command has an alias

Grep syslog today last hour
Uses date to grep de logfile for today and uses it to get the last hour logs. Can be used to get last minute logs or today's logs.

throttle bandwidth with cstream
this bzips a folder and transfers it over the network to "host" at 777k bit/s. cstream can do a lot more, have a look for example: $ echo w00t, i'm 733+ | cstream -b1 -t2 hehe :)

List only executables installed by a debian package
Safe for whitespaces in names.

Display IP : Count of failed login attempts
The lastb command presents you with the history of failed login attempts (stored in /var/log/btmp). The reference file is read/write by root only by default. This can be quite an exhaustive list with lots of bots hammering away at your machine. Sometimes it is more important to see the scale of things, or in this case the volume of failed logins tied to each source IP. The awk statement determines if the 3rd element is an IP address, and if so increments the running count of failed login attempts associated with it. When done it prints the IP and count. The sort statement sorts numerically (-n) by column 3 (-k 3), so you can see the most aggressive sources of login attempts. Note that the ':' character is the 2nd column, and that the -n and -k can be combined to -nk. Please be aware that the btmp file will contain every instance of a failed login unless explicitly rolled over. It should be safe to delete/archive this file after you've processed it.

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"

Find which service was used by which port number

I finally found out how to use notify-send with at or cron
The simplest way to do it. Works for me, at least. (Why are the variables being set?)

Stay in the loop…

Follow the Tweets.

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.


Subscribe to the feeds.

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,…):

Subscribe to the feed for: