Delete all delete markers in a versioned S3 bucket, to "undelete" all deleted objects that still have a version before the delete marker

delete_delete_markers.py

#!/usr/bin/env python

import sys
import boto

bucket_name = sys.argv[1]
s3 = boto.connect_s3()
bucket = s3.get_bucket(bucket_name)

for v in bucket.list_versions():
    if isinstance(v, boto.s3.deletemarker.DeleteMarker) and v.is_latest:
        print v.name, v.version_id, v.last_modified
        bucket.delete_key(v.name, version_id=v.version_id)