iftop is great tool to view almost live bandwidth usage distinguished by source-ip source-port destination-ip destination port.

I'm using it to see which client's ip is using most bandwidth. Now I would like to store output somewhere.

iftop uses ncurses so

iftop > log.txt

does not work as expected, result file is not readable.

Is there any tool like this which can be used to pipe output to a text file?

  • top tool has batch mode -b which enables you to save snapshot by redirecting output to a file, but iftop does not have such an option. – Khaled Apr 14 '12 at 14:47
  • thx Khaled for your reply, I know this already that's why I'm looking for iftop batch alternative. – mickula Apr 14 '12 at 14:49
  • You could also go for tcpdump if you want to be very precise... – gies0r Dec 28 '20 at 19:39

Since iftop-1.0pre3 (2014-01-01), a text output mode was added. This will be very useful to anyone trying to parse the output of iftop.

The command line option to activate text (batch) mode is:

-t          use text interface without ncurses

When using text mode, the following options are available:

-s num      print one single text output afer num seconds, then quit
-L num      number of lines to print

Use the -h option for help on iftop usage.

Example usage would be:

iftop -t > log.txt
iftop -t -s 180 > log.txt

If you want it to run in the background for 5 hours:

iftop -t -s 18000 > log.txt &

Check on background job with job command.


iptraf can log this level of detail. The output looks something like this:

Wed Apr 25 23:08:42 2012; UDP; eth0; 65 bytes; from to
Wed Apr 25 23:08:42 2012; UDP; eth0; 133 bytes; from to
Wed Apr 25 23:08:43 2012; UDP; eth0; 96 bytes; from to
Wed Apr 25 23:08:44 2012; UDP; eth0; 472 bytes; from to
Wed Apr 25 23:08:47 2012; ICMP; eth0; 159 bytes; from to; dest unrch (port)
  • What command line options do you use to get that output with iptraf? – Banjer Dec 2 '13 at 20:00
  • 1
    sudo iptraf -i eth0 -L /tmp/traffic_log – dwurf Dec 3 '13 at 3:39
  • A couple of notes: 1) I should run iptraf-ng on linux mint. 2) I should install car too by : sudo apt install ucommon-utils – Ehsan88 Apr 29 '19 at 2:50

Seems that iftop can't output to a text file(there is a feature request but it is not already implemented), in the meantime take a look at bwm-ng utility that is similar to iftop but allow to output on a CSV file.

Here's an example of usage :

bwm-ng -o csv -c 6 -T rate -I eth0 >> bandwidth.log
  • I already know this one, the problem is that output looks like: 1334421690;eth0;1909467.12;156131.73;2065598.88;78222;956643;2562.87;1956.09;4518.96;980;1284;0.00;0.00;0;0 1334421690;total;1909467.12;156131.73;2065598.88;78222;956643;2562.87;1956.09;4518.96;980;1284;0.00;0.00;0;0 1334421690;eth0;1934056.00;142336.00;2076392.00;71168;967028;2502.00;1874.00;4376.00;937;1251;0.00;0.00;0;0 1334421690;total;1934056.00;142336.00;2076392.00;71168;967028;2502.00;1874.00;4376.00;937;1251;0.00;0.00;0;0 so it's for whole interface not grouped by connected ip addresses – mickula Apr 14 '12 at 16:41
  • 1
    You can parse the CSV with a perl script for example and change the output format ... – aleroot Apr 14 '12 at 16:44
  • 3
    it's not about the format of file, it's that the stats is summary for interface not grouped by client IP – mickula Apr 15 '12 at 10:08

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