Glances is a free software (licensed under LGPL) to monitor your GNU/Linux or BSD operating system from a text interface. Glances uses the library libstatgrab to retrieve information from your system and it is developed in Python.
Hit Ctrl+Alt+T to open terminal and run following commands:
sudo apt-get install python-pip build-essential python-dev
sudo pip install Glances
sudo pip install PySensors
To start glances simply type glances in terminal.