vnstat
$ vnstat --help
vnStat 1.4 by Teemu Toivola <tst at iki dot fi>
-q, --query query database
-h, --hours show hours
-d, --days show days
-m, --months show months
-w, --weeks show weeks
-t, --top10 show top10
-s, --short use short output
-u, --update update database
-i, --iface change interface (default: eth1)
-?, --help short help
-v, --version show version
-tr, --traffic calculate traffic