[Tutor] Newbie: Help on comparing files

[Isr Gish]

This is the code I wrote to compare the files.

def compare(oldfilepth, newfilepth, sep):
	seplen = len(sep)
	olddata = getfiledata(oldfilepth)
	newdata = getfiledata(newfilepth)
	fw = file('\\Temp\\Code Breaker\\only in old.txt', 'w')

	index = 1
	while index != -1:
		index = olddata.find(sep)
		if index != -1:
			srchstr = olddata[:index]
			olddata = olddata[index + seplen:]
		else:
			srchstr = olddata
		srchlen = len(srchstr)
		fnd_indx = newdata.find(srchstr)
		if fnd_indx != -1:   #Substring was found
			newdata = newdata[:fnd_indx] + newdata[fnd_indx + srchlen + seplen:]
		else:   #The substring wasn't found
			fw.write(srchstr + sep)
	fw.close()
	fw = file('\\temp\\code breaker\\only in new.txt', 'w')
	fw.write(newdata)
	fw.close()

def getfiledata(filepth):
	fr = file(filepth)
	data = fr.read()
	fr.close()
	return data

This is the basic code. (it still needs a few enhancements).
What I want to know is, if there is a quicker way. For example if I would first split the whole file into list if the find  would be quicker.
Any other pointers about my code, would also be greatly appreciated.

Best Wishes
Isr Gish