bwm-ng

Filter to the interfaces or devices you want to watch, then choose current rate, maximum, total or recent average. bwm-ng can switch units among bytes, bits, packets and errors, and it offers curses, plain console, CSV or HTML output. The README documents CSV columns and an option to skip the initial all-zero sample. For HTML, coordinate page refresh with the collection interval. This is a local counter view, with input backends and disk-I/O support varying by operating system. Its published platform test list includes historical systems, so verify the intended backend on the actual build rather than assuming every listed feature works on every current OS.