mrtg user counts

I had a graph in mrtg of two variables: number of login sessions (the blue line, the count of users from the unix users command), and number of unique users logged in (the green solid area - formed by deduping the output of users).

I decided that the number of login sessions was a bit useless especially with people using screen. A more interesting graph is perhaps something else based on the number of users doing things rather than the number of things a user is doing. So I chose to count the number of (normal, not system) users who have at least one process running.

I count it this way:

#!/bin/bash

# first, unique users logged in
echo $(users | sed 's/ /\n/g' | sort | uniq | wc -l)

# number of users who have 3xxx user numbers and have a process running 
# 3xxx is the "normal user" range, though perhaps I could distinguish in other ways
U=$(ps -A --format user= | sort | uniq | while read a ; do id -u $a ; done | grep -e '3...' | wc -l)

echo $U
echo 0
echo 0

and here's the output: (green is logged-in users, blue is users with processes running)



If you click through to the full page, you might see the change happening in the middle of week 17 of 2011, which is the beginning of May.