Program:
- Add a dummy getopt(3) loop to handle --.
- Move interval parsing out into a separate function.
- Print a diagnostic for every invalid interval.
- Check for NaN and infinity.
- Improve bounds checks.
Manual page:
- Miscellaneous markup fixes.
- Reword DESCRIPTION section.
- Move text about GNU compatibility to STANDARDS section.
- Convert examples from csh to sh.
Sponsored by: Klara, Inc.