There doesn't seem to be a way to fetch a file by URL that meets both of these criteria:
- When run without --check, replaces the dest file with the contents of the source file if and only if they're different.
- When run with --check, correctly tells you whether anything would change if you run it without --check.
Doesn't that sound simple? I can't figure out how to do it, with either get_url or unarchive. :^( Is there a way?