Atomic file write operations (cross platform)

Question

How do I build up an atomic file write operation? The file is to be written by a Java service and read by python scripts.
For the record, reads are far greater than writ

Answer 1

At least on POSIX platforms, leave out step 3 (delete old file). In POSIX, rename within a filesystem is guaranteed to be atomic, and renaming on top of an existing file replaces it atomically.