標準的なPOSIX Cron式の5つのフィールドの並び順は？

左から順に：1. 分 (0-59)、2. 時 (0-23)、3. 日 (1-31)、4. 月 (1-12)、5. 曜日 (0-7、0と7は日曜日) となります。

What is the difference between standard 5-field cron and Quartz 6-field cron?

Standard cron begins at the minute level (5 fields). Quartz begins with a seconds field (0-59) followed by minute, hour, day-of-month, month, day-of-week, and optional year, providing sub-minute scheduling precision.

Why should recurring production cron jobs always be scheduled in UTC?

Scheduling in local time zones creates vulnerabilities during Daylight Saving Time (DST) clock adjustments, causing jobs to either execute twice (autumn rollback) or be skipped entirely (spring jump). UTC has no DST shifts.

How does cron handle both Day-of-Month and Day-of-Week in the same rule?

Under standard POSIX cron specifications, when both Day-of-Month and Day-of-Week are non-wildcard values, cron treats them with logical OR logic. The job executes whenever either condition evaluates to true.

Can I test and parse non-standard step expressions like */15 or ranges like 9-17?

Yes. The X114 parser fully evaluates step expressions (*/N), ranges (A-B), comma lists (A,B,C), and range steps (A-B/N) in real time with comprehensive error checking.

Cron式・クーロン生成＆解析ツール

API近日公開

Cron式を視覚的に生成・解析・検証。自然言語による解説と直近の実行予定時刻をリアルタイム表示。

Presets:

Cron ExpressionValid POSIX Cron

Standard 5-part cron syntax: [minute] [hour] [day-of-month] [month] [day-of-week]

Minute00 - 59

Hour90 - 23

Day (Month)*1 - 31

Month*1 - 12

Day (Week)1-50 - 7 (Sun-Sat)

Human Translation

At 9:00 AM (09:00) on every weekday (Monday through Friday).

Interactive Field Builder

Or specify custom minute pattern:

Next 5 Scheduled Executions

Calculated in local timezone

1Mon, Oct 19, 2026

09:00:00(UTC: 2026-10-19T09:00:00Z)

2Tue, Oct 20, 2026

09:00:00(UTC: 2026-10-20T09:00:00Z)

3Wed, Oct 21, 2026

09:00:00(UTC: 2026-10-21T09:00:00Z)

4Thu, Oct 22, 2026

09:00:00(UTC: 2026-10-22T09:00:00Z)

5Fri, Oct 23, 2026

09:00:00(UTC: 2026-10-23T09:00:00Z)

Production Crontab Command Generator

Generate an immediate copy-paste command for your Linux server or Docker container crontab file (`crontab -e`).

Target Executable / Script Path:

crontab -e entry

0 9 * * 1-5 /usr/bin/python3 /opt/scripts/backup.py >> /var/log/cron.log 2>&1

API バージョンが近日公開

Cron Expression Generator & Parser の API が利用可能になったときにお知らせします。

概要