vnstati
PNG image output support for vnStat.
TLDR
Output a summary of the last 2: months, days, and all-time
$ vnstati --summary --iface [network_interface] --output [path/to/output.png]
Output the 10 most traffic-intensive days of all time
$ vnstati --top10 --iface [network_interface] --output [path/to/output.png]
Output monthly traffic statistics from the last 12 months
$ vnstati --months --iface [network_interface] --output [path/to/output.png]
Output hourly traffic statistics from the last 24 hours
$ vnstati --hours --iface [network_interface] --output [path/to/output.png]
