Title: Realtime bandwidth terminal graph visualization

	Title: Realtime bandwidth terminal graph visualization
	Author: Solène
	Date: 19 July 2019
	Tags: openbsd ttyplot
	Description:

	If for some reasons you want to visualize your bandwidth traffic on an
	interface (in or out) in a terminal with a nice graph, here is a small
	script
	to do so, involving ttyplot, a nice software making graphics in a
	terminal.

	The following will works on OpenBSD.
	You can install ttyplot by `pkg_add ttyplot` as root, ttyplot package
	appeared
	since OpenBSD 6.5.

	For Linux, the [ttyplot official
	website](https://github.com/tenox7/ttyplot)
	contains tons of examples.


	### Example

	Output example while updating my packages:

	IN Bandwidth in KB/s
	↑ 1499.2 KB/s#
	│ #
	│ #
	│ #
	│ ##
	│ ##
	│ 1124.4 KB/s##
	│ ##
	│ ##
	│ ##
	│ ##
	│ ##
	│ 749.6 KB/s ##
	│ ##
	│ ##
	│ ##
	#
	│ ## # # # #
	##
	│ ## # ### # ## # # # ##
	## # # ##
	│ 374.8 KB/s ## ## #### # # ## # # ### ## ## ### #
	## ### # # # # ## # ##
	│ ## ### ##### ########## ############# ### # ##
	### ##### #### ## ## ###### ## ##
	│ ## ### ##### ########## ############# ### ####
	### ##### #### ## ## ## ###### ## ###
	│ ## ### ##### ########## ############## ### ####
	### ##### #### ## ## ######### ## ####
	│ ## ### ##### ##############################
	######### ##### #### ## ## ############ ####
	│ ## ###
	#################################################### #### ##
	#####################
	│ ## ###
	####################################################
	#############################

	└──────────────────────�
	�───────────────────────�
	��───────────────────────
	───────────────────────�
	�──────→
	# last=422.0 min=1.3 max=1499.2 avg=352.8 KB/s
	Fri Jul 19 08:30:25 2019

	github.com/tenox7/ttyplot 1.4

	In the following command, we will use trunk0 with INBOUND traffic
	as the
	interface to monitor.

	At the end of the article, there is a command for displaying both in
	and out at
	the same time, and also instructions for customizing to your need.

	Article update: the following command is extremely long and
	complicated, at
	the end of the article you can find a shorter and more efficient
	version,
	removing most of the awk code.

	You can copy/paste this command in your OpenBSD system shell, this will
	produce
	a graph of trunk0 inbound traffic.

	{ while :; do netstat -i -b -n ; sleep 1 ; done } \| awk
	'BEGIN{old=-1} /^trunk0/ { if(!index($4,":") && old>=0) { print
	($5-old)/1024 ; fflush ; old = $5 } if(old==-1) { old=$5 } }' \|
	ttyplot -t "IN Bandwidth in KB/s" -u "KB/s" -c "#"

	The script will do an infinite loop doing `netstat -ibn` every second
	and
	sending that output to awk.
	You can quit it with Ctrl+C.


	## Explanations

	Netstat output contains total bytes (in or out) since system has
	started so awk
	needs to remember last value and will display the difference between
	two
	output, avoiding first value because it would make a huge spike (aka
	the total
	network transfered since boot time).

	If I decompose the awk script, this is a lot more readable.
	Awk is very readable if you take care to format it properly as any
	source code!

	#!/bin/sh
	{ while :;
	do
	netstat -i -b -n
	sleep 1
	done
	} \| awk '
	BEGIN {
	old=-1
	}
	/^trunk0/ {
	if(!index($4,":") && old>=0) {
	print ($5-old)/1024
	fflush
	old = $5
	}
	if(old==-1) {
	old = $5
	}
	}' \| ttyplot -t "IN Bandwidth in KB/s" -u "KB/s" -c "#"


	### Customization

	+ replace trunk0 by your interface name
	+ replace both instances of $5 by $6 for OUT traffic
	+ replace /1024 by /1048576 for MB/s values
	+ remove /1024 for B/s values
	+ replace 1 in sleep 1 by another value if you want to have the
	value every
	n seconds


	### IN/OUT version for both data on the same graph + simpler

	Thanks to leot on IRC, netstat can be used in a lot more efficient way
	and remove all the awk parsing!
	ttyplot supports having two graphs at the same time, one being in
	opposite color.

	netstat -b -w 1 -I trunk0 \| awk 'NR>3 { print $1/1024; print
	$2/1024; fflush }' \| ttyplot -2 -t "IN/OUT Bandwidth in KB/s" -u "KB/s"
	-c "#"