python script for rooting out unused jars

jarjarblinks.py

#!/usr/local/bin/python

import subprocess
from os import listdir,rename,mkdir,system
from os.path import isfile, join

try:
    mkdir('bad')
except:
    print "already exists"

path = 'lib'
jars = [ f for f in listdir(path) if isfile(join(path,f)) and f.endswith('jar')]

for j in jars:
    print "moving " + j 
    rename ('lib/'+j, 'bad/'+j)
    rtcode = -1
    try:
        rc = system("ant junit")
        rtcode = rc
        print "returncode"
        print rtcode
    except Exception as e:
        print "failed! " + e.message

    if rtcode != 0:
        print "bad returncode, moving file back: " + j 
        rename ('bad/'+j, 'lib/'+j)