vnstat

VNstat is a command line tool used for monitoring network traffic and bandwidth usage on Linux systems. It keeps track of data transfers on network interfaces and provides detailed statistics in a simple, easy-to-read format. The tool works by analyzing the packets sent and received on each network interface and stores the collected data in a database for future reference. VNstat provides information such as daily and monthly download and upload totals, hourly and top-level statistics, data transfer rates, and peak traffic times. It supports both IPv4 and IPv6 protocols and can monitor multiple network interfaces simultaneously. It also offers the ability to generate graphical output using various templates and integration with third-party scripts and tools.