Nload

nload version 0.7.4
Copyright (C) 2001 - 2012 by Roland Riegel <feedback@roland-riegel.de>
nload comes with ABSOLUTELY NO WARRANTY. This is free software, and you are
welcome to redistribute it under certain conditions. For more details see the
GNU General Public License Version 2 (http://www.gnu.org/copyleft/gpl.html).
Command line syntax:
nload [options] [devices]
nload --help|-h
Options:
-a period Sets the length in seconds of the time window for average
 calculation.
 Default is 300.
-i max_scaling Specifies the 100% mark in kBit/s of the graph indicating the
 incoming bandwidth usage. Ignored if max_scaling is 0 or the
 switch -m is given.
 Default is 10240.
-m Show multiple devices at a time; no traffic graphs.
-o max_scaling Same as -i but for the graph indicating the outgoing bandwidth
 usage.
 Default is 10240.
-t interval Determines the refresh interval of the display in milliseconds.
 Default is 500.
-u h|b|k|m|g Sets the type of unit used for the display of traffic numbers.
 H|B|K|M|G h: auto, b: Bit/s, k: kBit/s, m: MBit/s etc.
 H: auto, B: Byte/s, K: kByte/s, M: MByte/s etc.
 Default is h.
-U h|b|k|m|g Same as -u, but for a total amount of data (without "/s").
 H|B|K|M|G Default is H.
devices Network devices to use.
 Default is to use all auto-detected devices.
--help
-h Print this help.
example: nload -t 200 -i 1024 -o 128 -U M
The options above can also be changed at run time by pressing the 'F2' key.