Script help

[Jeff Elkins <jeffelkins@earthlink.net>]

I'm doing a lot of work with a Sharp Zaurus which requires several re-flashes  
of the box daily - With my initrd.bin, ssh keys on the Z regenerate with each 
flash. As a consequence, my host .ssh/known_hosts is frequently outdated and 
I must edit it to remove references to z,xxx.xxx.xxx.xxx.

I'd like to gen up a script to nuke references in .ssh/known_hosts to the 
Zaurus. It's trivial to edit known_hosts, but I'd like to eliminate this 
step.

Can someone point me in the right direction? 

TIA

Jeff Elkins