We've been using PlantUML in the past to outline dependencies and relations between classes or to simply get the relations in databases right. There is a nice Confluence plugin and serveral editors availabe, that let you edit your PlantUML file in the browser and show the generated graph image right beside it. That is neat, but I prefere my own computer and I like vim. But re-running the command to generate the image every 10 seconds manually is tedious.

So, here is a quick and dirty hack that generates a new image for your .plantuml file whenever it has been created or changed. Just start the watchdog in the folder you want to work in and plantwatchdog.py takes care of the rest. Don't forget to take a look at the dependencies first. You'll need sh, watchdog and of course the plantuml.jar. Yeah, that also means you'll need to have a JRE. You'll also need to create a shell script file named plantumlpipe with the correct path to your plantuml.jar somewhere in $PATH:

#! /usr/bin/env sh
java -Djava.awt.headless=true -jar /<the_path_to>/plantuml.jar -pipe