Regex Tester & Validator

Validates the minute field (first column) of a crontab entry. Accepts a literal asterisk (*) for every minute, step values like */15, single minute values 0-59, ranges like 5-30, and comma-separated pairs like 5,10. Note the limitation that ranges and comma lists only allow a single-digit first value (0-9), so entries like 15-30 or 5,10,15 won't match. Useful for basic cron schedule validation with multiline input.