I’ve been using Ubuntu 18.04 for a while. But every time I boot into it, bluetooth is just turned on, even though I don’t use bluetooth devices and don’t actually have one.
Browsing through some forums, I found two clear ways1.
The first one suggested that we should take a look at the configuration file /etc/bluetooth/main.conf.
In this file we can find an entry named AutoEnable=true, and we just change the value to false.
However, this doesn’t work on my system.
The second one taught us to use systemctl, which looks like a legit way. So I could check the status of Bluetooth with,
sudo systemctl status bluetooth.service
And simply deactivated it by,
sudo systemctl disable bluetooth.service
This works! But others also stated in the comment that this method could disable not only Bluetooth but actually more functions. Well, let’s see if something’d go wrong in the near future.