Here's script I wrote out of boredom, for download speed test:
#!/bin/bash
get_ispeed() {
echo $(ifconfig eth0 | grep bytes | grep RX | cut -d ':' -f 2 | cut -d ' ' -f 1);
}
for((;;));
do
s1=`get_ispeed`;
sleep 1s;
s2=`get_ispeed`;
d=$(($s2-$s1));
echo $(($d / 1000))" kB/s";
done
Not sure if it's "doing the job", though I'm not true bashist :p
Since ifconfig yields RX bytes, I divide it by 1000 to get kB/s
I don't think you're really looking for link speed, this is the dedicated connection speed of your connection. If you have ethtool installed (in repos) you can use this command to get your link speed:
$ sudo ethtool eth0 | grep -i speed
Speed: 100Mb/s
You want to see your bandwidth speed. How much of the total speed you're using over a given amount of time. There are a couple of ways to get the bytes read by the eth0 interface:
$ cat /sys/class/net/eth0/statistics/rx_bytes
3431530366
There is also /proc/net/dev, which I believe is the kernel structure that provides the data for ifconfig:
$ cat /proc/net/dev
Inter-| Receive | Transmit
face |bytes packets errs drop fifo frame compressed multicast|bytes packets errs drop fifo colls carrier compressed
lo:629956414 572909 0 0 0 0 0 0 629956414 572909 0 0 0 0 0 0
eth0:3431888253 329701689 0 0 0 0 0 359127 831203319 353144288 0 0 0 0 0 0
sit0: 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Better still would be to use an actual tool for measuring your bandwidth usage. There are many options here:
use wget/curl
These are pretty straightforward. Pick a large file to download and see the stats reported by either tool after it's completed.
$ wget --output-document=/dev/null http://speedtest.wdc01.softlayer.com/downloads/test500.zip
-or-
$ curl -O /dev/null http://speedtest.wdc01.softlayer.com/downloads/test500.zip
use a cli monitoring tool
There are numerous tools in this category. Here are a couple to get you started.
use speedtest-cli
This makes use of the venerable speedtest.net website from the command line.
$ ./speedtest-cli
Retrieving speedtest.net configuration...
Retrieving speedtest.net server list...
Testing from Comcast Cable (x.x.x.x)...
Selecting best server based on ping...
Hosted by FiberCloud, Inc (Seattle, WA) [12.03 km]: 44.028 ms
Testing download speed........................................
Download: 32.29 Mbit/s
Testing upload speed..................................................
Upload: 5.18 Mbit/s
use iperf
For this you'll setup your own server and client and then measure the bandwidth performance between two of your computers. This is a better in the sense that you'll get a more accurate picture of your computer/network performance than depending on the performance of a specific internet target.
on server:
$ iperf -s
on client:
$ iperf -c myserver.mydom
------------------------------------------------------------
Client connecting to 192.168.1.1, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.3 port 52143 connected with 192.168.1.1 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 113 MBytes 94.7 Mbits/sec
I'm really agreed with your question and answers, thus, I can really do this in a single line:
m1=`cat /sys/class/net/eth0/statistics/tx_bytes` ; sleep 10s ; m2=`cat /sys/class/net/eth0/statistics/rx_bytes` ; echo $((($m2-$m1)/10240))
And it prints pretty well.
In a more sophisticated way:
#!/bin/bash
intervalo=3
info="/sys/class/net/"
cd $info
for interface in eth*
do
rx1=`cat $info$interface/statistics/rx_bytes`
tx1=`cat $info$interface/statistics/tx_bytes`
`sleep $((intervalo))s`
rx2=`cat $info$interface/statistics/rx_bytes`
tx2=`cat $info$interface/statistics/tx_bytes`
echo $interface
echo ----
echo RX: $((($rx2-$rx1)/($intervalo*1024))) Kbps
echo TX: $((($tx2-$tx1)/($intervalo*1024))) Kbps
done
That works fine, but can be improved using arrays to save each interface result, so it would only need to do a sleep for all the interfaces, and not one by any of them.
The advertised speed and the actual speed of the link can be different
sudo ethtool enp1s0
Settings for enp1s0:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
This reports the actual link speed as negotiated between both devices on each end of the link. My laptops network card the local switch I connect to.
Whereas the actual speed reported by these tools is
sudo mii-tool enp1s0
enp1s0: negotiated 100baseTx-FD flow-control, link ok
sudo ethtool enp1s0 | grep -i speed
Speed: 100Mb/s
I will only ever reach the link speed when I download something connected in the same LAN at the same speed.
If I download a file from a server on the same LAN. I will get the full 100Mb/s.
So where I connet to will make a difference to the speed I get.
