[Tutor] Search and Replace

[VanL]

Hello,

I just did a search and replace script.  It works, but I am wondering if 
there is something better.

I use os.path.walk to walk through a directory tree, calling the 
visitfile function on each file (quoted below).

By the way, I know that I scan through the file multiple times; I have a 
version that doesn't do that, but I did it this way first to get a 
little better debugging output.  Just ignore that inefficiency.

def visitfile(fname, sarstrings):
	stext, rtext = sarstrings[0], sarstrings[1]
	matcher = re.compile(stext) 
	try:
		if not listonly:
			if os.path.splitext(fname)[1] in skipexts:
				debug('Skipping: ' + fname)
			elif string.find(open(fname).read(), stext) != -1:
				debug('%s has %s' % (fname, stext))
				linelist = open(fname, 'rb+').readlines()
				file = open(fname, 'wb', 0)
				for line in linelist:
					line = matcher.sub(rtext, line)
					file.write(line)
				file.close()
				fcount = fcount + 1
	except: pass 




Like I said, this works... but it worries me a little because I truncate 
the file to 0 length and then rewrite it from the in-memory list.  This 
could very easily be a problem for very large files.  Moreover, if the 
script is interrupted, the curent file will be lost.

Is there a better way to do an in-place change?  

Thanks,

Van