I often want to see how much bandwidth is consumed by my network interfaces and how this is happening. There’s plenty of tools available in the linux world to monitor your network activity.
If you’re a Ubuntu or Debian user you can try the ones I use by installing the following packages.
sudo apt-get install iptraf ethstatus dstat iftop ifstat nload bwm-ng
Then try each one of those on your command line and have fun exploring what they can do.
If they’re not on the path of your user account, then try them using sudo.
eg. sudo iftop
If this short list of the tools I use does not satisfy you, I suggest you read this more comprehensive list of monitoring tools