import boto

AWS_USER = ''
AWS_KEY = ''
SOURCE_BUCKET = ''
DESTINATION_BUCKET = ''

b_count = 0
count = 1
conn = boto.connect_s3(AWS_USER, AWS_KEY)
rs = conn.get_all_buckets()

for bucket in rs:
    if bucket.name == SOURCE_BUCKET:
        old_bucket = bucket
    elif bucket.name == DESTINATION_BUCKET:
        new_bucket = bucket

print "counting old_bucket..."
for i in old_bucket.list():
    b_count += 1

for key in old_bucket:
    if not new_bucket.get_key(key.name):
        print "%s / %s: copying %s" % (count, b_count, key.name)
        key.copy(DESTINATION_BUCKET, key.name)
    else:
        print "%s / %s: leaving %s" % (count, b_count, key.name)
    count += 1