Doing some work trying to update J2C resources defined in WebSphere using Rational Automation Framework, actually about the same thing as described in the article “A step-by-step guide to automating the deployment of a data source by using Rational Build Forge” and I needed to do some changes in jaas.xml. Won’t go into the details why editing XML using for instance “normal” Perl is hard, but I ended up using Python and ElementTree to edit the file with a structure like this

<jaas>
	<JAASAuthData 
		alias="dmgr/databaseuser" 
		description="The database user" 
		password="thepassword" 
		userId="dbid">
	</JAASAuthData>
</jaas>

Used plenty of sources to help me out, but I do think I did use http://effbot.org/ the most – super when it comes to figuring out Python, but http://www.rexx.com/~dkuhlman/pyxmlfaq.html was also of great help!

The script I created is available here updateJaas.py The script is bound to changing jaas.xml-files, but it should be quite easy to change it for other needs as well.