How can I get the current network interface throug

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Tools such as MRTG provide network throughput / bandwidth graphs for the current network utilisation on specific interfaces, such as eth0. How can I return that information at the command line on Linux/UNIX?

Preferably this would be without installing anything other than what is available on the system as standard.

Answer 1

If you want just to get the value, you can use simple shell oneliner like this:

S=10; F=/sys/class/net/eth0/statistics/rx_bytes; X=`cat $F`; sleep $S; Y=`cat $F`; BPS="$(((Y-X)/S))"; echo $BPS

It will show you the average "received bytes per second" for period of 10 seconds (you can change period by changing S=10 parameter, and you can measure transmitted BPS instead of received BPS by using tx_bytes instead of rx_bytes). Don't forget to change eth0 to network device you want to monitor.

Of course, you are not limited to displaying the average rate (as mentioned in other answers, there are other tools that will show you much nicer output), but this solution is easily scriptable to do other things.

For example, the following shell script (split into multiple lines for readability) will execute offlineimap process only when 5-minute average transmit speed drops below 10kBPS (presumably, when some other bandwidth-consuming process finishes):

#!/bin/sh
S=300; F=/sys/class/net/eth0/statistics/tx_bytes
BPS=999999
while [ $BPS -gt 10000 ]
do
  X=`cat $F`; sleep $S; Y=`cat $F`; BPS="$(((Y-X)/S))";
  echo BPS is currently $BPS
done
offlineimap

Note that /sys/class/... is Linux specific (which is ok as submitter did choose linux tag), and needs non-archaic kernel. Shell code itself is /bin/sh compatible (so not only bash, but dash and other /bin/sh implementations will work) and /bin/sh is something that is really always installed.

Answer 2

Besides iftop and iptraf, also check:

• bwm-ng (Bandwidth Monitor Next Generation)

and/or

• cbm (Color Bandwidth Meter)

ref: http://www.powercram.com/2010/01/bandwidth-monitoring-tools-for-ubuntu.html

Answer 3

nload is a great tool for monitoring bandwidth in real time and easily installed in Ubuntu or Debian with sudo apt-get install nload.

Device eth0 [10.10.10.5] (1/2):
=====================================================================================
Incoming:


                               .         ...|    
                               #         ####|   
                           .. |#|  ...   #####.         ..          Curr: 2.07 MBit/s
                          ###.###  #### #######|.     . ##      |   Avg: 1.41 MBit/s
                         ########|#########################.   ###  Min: 1.12 kBit/s
             ........    ###################################  .###  Max: 4.49 MBit/s
           .##########. |###################################|#####  Ttl: 1.94 GByte
Outgoing:
            ##########  ###########    ###########################
            ##########  ###########    ###########################
            ##########. ###########   .###########################
            ########### ###########  #############################
            ########### ###########..#############################
           ############ ##########################################
           ############ ##########################################
           ############ ##########################################  Curr: 63.88 MBit/s
           ############ ##########################################  Avg: 32.04 MBit/s
           ############ ##########################################  Min: 0.00 Bit/s
           ############ ##########################################  Max: 93.23 MBit/s
         ############## ##########################################  Ttl: 2.49 GByte

Another excellent tool is iftop, also easily apt-get'able:

             191Mb      381Mb                 572Mb       763Mb             954Mb     
└────────────┴──────────┴─────────────────────┴───────────┴──────────────────────
box4.local            => box-2.local                      91.0Mb  27.0Mb  15.1Mb
                      <=                                  1.59Mb   761kb   452kb
box4.local            => box.local                         560b   26.8kb  27.7kb
                      <=                                   880b   31.3kb  32.1kb
box4.local            => userify.com                         0b   11.4kb  8.01kb
                      <=                                  1.17kb  2.39kb  1.75kb
box4.local            => b.resolvers.Level3.net              0b     58b    168b
                      <=                                     0b     83b    288b
box4.local            => stackoverflow.com                   0b     42b     21b
                      <=                                     0b     42b     21b
box4.local            => 224.0.0.251                         0b      0b    179b
                      <=                                     0b      0b      0b
224.0.0.251           => box-2.local                         0b      0b      0b
                      <=                                     0b      0b     36b
224.0.0.251           => box.local                           0b      0b      0b
                      <=                                     0b      0b     35b


─────────────────────────────────────────────────────────────────────────────────
TX:           cum:   37.9MB   peak:   91.0Mb     rates:   91.0Mb  27.1Mb  15.2Mb
RX:                  1.19MB           1.89Mb              1.59Mb   795kb   486kb
TOTAL:               39.1MB           92.6Mb              92.6Mb  27.9Mb  15.6Mb

Don't forget about the classic and powerful sar and netstat utilities on older *nix!

Answer 4

iftop does for network usage what top(1) does for CPU usage -- http://www.ex-parrot.com/~pdw/iftop/

I don't know how "standard" iftop is, but I was able to install it with yum install iftop on Fedora.

Answer 5

You can use iperf to benchmark network performance (maximum possible throughput). See following links for details:

http://en.wikipedia.org/wiki/Iperf

https://iperf.fr/

https://code.google.com/p/iperf/

Answer 6

• dstat - Combines vmstat, iostat, ifstat, netstat information and more
• iftop - Amazing network bandwidth utility to analyse what is really happening on your eth
• netio - Measures the net throughput of a network via TCP/IP
• inq - CLI troubleshooting utility that displays info on storage, typically Symmetrix. By default, INQ returns the device name, Symmetrix ID, Symmetrix LUN, and capacity.
• send_arp - Sends out an arp broadcast on the specified network device (defaults to eth0), reporting an old and new IP address mapping to a MAC address.
• EtherApe - is a graphical network monitor for Unix modeled after etherman. Featuring link layer, IP and TCP modes, it displays network activity graphically.
• iptraf - An IP traffic monitor that shows information on the IP traffic passing over your network.

More details: http://felipeferreira.net/?p=1194