Linux Server Hacks, Volume Two

Hack #84. Send Log Messages to Your Jabber Client

Use hidden features of syslog and a quick script to send syslog messages straight to your desktop.

So you've finally gotten your machine room set up with centralized logging. Now you no longer need to open 50 different terminal windows to tail logs on all of your web servers. Instead, you just open one session to the central log host, tail the log, and go about your business.

But what if you could have the really important log messages, maybe only those going to the auth.warning facility, sent directly to your desktop in a way that will catch your attention even if you leave and come back only after the message has already scrolled by in your tail session?

You can actually accomplish this in a number of ways, but my favorite is by sending anything that comes through my syslog filter to my Jabber client. As most of you probably know, Jabber is an open source instant messaging protocol supported by Linux clients such as GAIM and Kopete.

This hack works because it turns out that syslog has the ability to send or copy messages to a named pipe (or FIFO). A pipe in the Linux world is a lot like a pipe in a plumber's world: you send something in one end, and it comes out (or is accessible through) the other end. By this logic, you can see that if I can have warnings sent to a pipe, I should be able to attach to that pipe some form of faucet from which I can access those messages. This is exactly what we'll do. For example, to send only those ...