rename.py

#! /usr/bin/python

import os, os.path, re

counter = 0

for root, _, files in os.walk("./"):
    for f in files:
        fullpath = os.path.join(root, f)
        replaced = re.sub("_OST50GRID\w*", "", f)
        newfullpath = os.path.join(root, replaced)
        if fullpath != newfullpath:
            print 'Renamed: "' + fullpath + '" to "' + newfullpath
            counter += 1
        os.rename(fullpath, newfullpath)

print 'Done. Renamed ' + str(counter) + ' files.'