Question 1

What's the difference between cron and crontab?

Accepted Answer

Cron is the time-based job scheduler in Unix-like systems. Crontab (cron table) is the file where you define your scheduled tasks using cron expressions. You edit the crontab file to add, modify, or remove scheduled jobs.

Question 2

Why does my cron job run at the wrong time?

Accepted Answer

The most common issue is timezone mismatch. Cron typically runs in the server's system timezone (often UTC), not your local timezone. Always verify your server's timezone setting and convert your desired schedule accordingly.

Question 3

Can I schedule a job to run every 2 weeks?

Accepted Answer

Standard cron cannot directly express 'every 2 weeks.' You can schedule it weekly and add logic in your script to check if it's the right week, or use a more advanced scheduler that supports extended syntax.

Question 4

What happens if a cron job doesn't finish before the next run?

Accepted Answer

Cron will start a new instance regardless of whether the previous one finished. This can cause overlapping executions. To prevent this, use a lock file mechanism in your script or tools like flock.

Question 5

How do I test my cron expression without waiting?

Accepted Answer

Use this tool's 'Next 5 Scheduled Runs' feature to verify your expression will execute when expected. You can also temporarily set a frequent schedule (like */1) to test, then change it back.

Question 6

cronExpressionBuilder.faq.q6.question

Accepted Answer

cronExpressionBuilder.faq.q6.answer

Question 7

cronExpressionBuilder.faq.q7.question

Accepted Answer

cronExpressionBuilder.faq.q7.answer

Question 8

cronExpressionBuilder.faq.q8.question

Accepted Answer

cronExpressionBuilder.faq.q8.answer

Cron Expression Builder

Generated Expression

Next 5 Scheduled Runs

Field Summary

Related Tools

HTTP Status Code Lookup

Base64 Encoder/Decoder

Regex Tester

SQL Formatter