Testing your internet speed regularly

Use crontab and a bit of Python to store speedtest results in a CSV.

This post is making use of the speedtest command line version of Ookla’s speedtest tools, which you can get here for various OSes: https://www.speedtest.net/apps/cli

Specifically, I was looking for a linux solution, and while it’s straight forward on the Mac, where the --csv flag produces a CSV string that includes a proper timestamp of the measurement, the interface or API for the homebrew CLI versions of Mac and Linux are quite different.

On macOS, one can do

speedtest --csv

and the output will contain a column with a timestamp which is important for keeping track of the measurements.

On Linux, however, for getting a CSV output, one needs to do

speedtest --format=csv

and unfortunately here we do NOT get a timestamp in the output. There is the option to use --format=json which actually does provide a timestamp, but I don’t want to deal with JSON parsing for this simple thing.

So I added some bits of Python to catch the output of speedtest and add a timestamp to its CSV line before appending it to a record of measurements.

The sh package is a very useful one-file package that enables you to call system programs in a function-like manner, with proper redirection utilities of any incoming output etc. BTW, I tried to simply work with the returned object, but it wasn’t simply the text, it was some kind of CommandObject and the docs are not clear on how to get the text out of the command object, probably easy but I didn’t inspect it. So maybe below script can be made even easier, without a callback function but directly working with the returned object.

The header line by the way one can get by adding the --output-header flag to the above command. I then just went ahead and added , time to the header line, so that the header is complete for a quick pandas import down the road.

Note that the numbers of speedtest are bytes/s, so one does need to do some math to convert to the usual Mbps.

Here’s my script:


I forgot to add how to run it regularly using crontab:


crontab -e

and an editor should pop up.

The first cryptical looking syntax of crontab, the service that enables you to regularly execute any program or script on your machine is actually pretty simple, HelpUbuntu has a good intro here: https://help.ubuntu.com/community/CronHowto

In short, to run a script every hour on the minute 22 you put this into your crontab file:

22 * * * * /path/to/script/to/run.py

Hope it helps someone. If anybody wants to see how to quickly analyze and plot the file using pandas let me know, but I figure most of my readers will know that?

Let me know, put any questions or comments you may have on my Twitter feed! Comment

Michael Aye
Michael Aye
Research Scientist in Planetary Science

My research interests include remote sensing of surfaces, related machine learning studies and open source software.