For the longest time I had my systems cat Syslog to an lpr... anytime someone did something, I’d hear a bzzzzzt. Usually about 5 times a day. Maybe a dozen. Then one morning I came into work and there was a whole box of paper on the floor and the printer is still bzzt, bzzt, bzzt... it was a hacker who had decided to follow some instructions he found on the web and hack my system. Every time he’d do something he’d erase his steps... but he never checked to see that all his movements were being printed!