Glasswire is a great free app to view data usage but it is not available for Linux. You can use these commands to install a CLI based alternative in Ubuntu, Linux Mint, MX Linux and other Debian based systems.
Install nethogs
sudo apt install nethogs
You can use nethog with total bandwidth monitored per MB since it started with:
sudo nethogs -v 3
SOURCE: Linux: per-application traffic monitoring (not nethogs)
https://superuser.com/questions/72186...