Display live Linux system stats (memory, CPU, IO, etc) in a pretty web-page, with charts and everything.
Linux (and many other UNIXy operating systems) have a command line tool called vmstat for monitoring system stats.
It looks like this (a new line is output every second showing the latest values):
$ vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
3 0 43652 2742600 453820 2829164 0 0 1 10 0 0 6 1 93 0
1 0 43652 2742784 453820 2829164 0 0 0 0 3106 5701 11 1 87 0
0 0 43652 2742908 453820 2829164 0 0 0 0 3898 6703 11 2 87 0
1 0 43652 2743672 453820 2829164 0 0 0 32 3844 6708 11 2 87 0
2 0 43652 2743980 453820 2829164 0 0 0 80 4130 7164 11 2 87 0
Useful, but fugly.
This is a tiny application that streams these stats over a WebSocket using websocketd and charts them using SmoothieCharts.
Why not? A handy little process to install on machines you care about. After building this for my own needs, I thought it would make a great little demo.
And if you want to use it or hack on it yourself, here it is.
See ./run script for instructions.