newbe question about removing items from one file to another file

[Eric_Dexter at msn.com]

def simplecsdtoorc(filename):
    file = open(filename,"r")
    alllines = file.read_until("</CsInstruments>")
    pattern1 = re.compile("</")
    orcfilename = filename[-3:] + "orc"
    for line in alllines:
        if not pattern1
             print >>orcfilename, line

I am pretty sure my code isn't close to what I want.  I need to be able
to skip html like commands from <defined> to <undefined> and to key on
another word in adition to </CsInstruments> to end the routine

I was also looking at se 2.2 beta but didn't see any easy way to use it
for this or for that matter search and replace where I could just add
it as a menu item and not worry about it.

thanks for any help in advance