I prefer to stick scheduled tasks in /etc/crontab so I can see at a glance what's scheduled to run, regardless of which user the task runs as.

The only gotcha is that the format isn't validated on save, unlike crontab -e -- so a stray character can quietly break the entire cron.

Is there a way to validate the /etc/crontab format before/after save?

  • 6
    If, like me, you came here looking for a simple (non-scriptable) way to tell you whether you'd got your cron entry right, you might be interested in cronchecker.net — it's an online validator for cron entries with human-friendly output. Dec 20, 2014 at 11:18

7 Answers 7


The only reliable way I found is to check the log.

cron checks /etc/crontab every minute, and logs a message indicating that it has reloaded it, or that it found an error.

So after editing, run this:

sleep 60; grep crontab /var/log/syslog | tail

Or, to not wait a full minute, but only until the next minute + 5 seconds:

sleep $(( 60 - $(date +%S) + 5 )) && grep cron /var/log/syslog | tail

Example output with an error:

Jan  9 19:10:57 r530a cron[107258]: Error: bad minute; while reading /etc/crontab
Jan  9 19:10:57 r530a cron[107258]: (*system*) ERROR (Syntax error, this crontab file will be ignored)

Good output:

Jan  9 19:19:01 r530a cron[107258]: (*system*) RELOAD (/etc/crontab)

That's on Debian 8. On other systems, cron might log to a different file.

(I thought I could avoid hunting for the right log file by using systemd's journalctl -u cron, but that didn't show me these log entries, and actually seems to have stopped logging cron events 2 days ago for some reason)

  • 1
    Tested on FreeBSD 10.3. Works like a charm, just replace log path with /var/log/cron
    – Jette
    Aug 5, 2019 at 8:15
  • Path to cron log in Rocky 9 is also /var/log/cron like FreeBSD 10.3.
    – Gwi7d31
    Jul 24 at 14:33

Another more recent solution is the python script chkcrontab

  • 2
    It doesn't check users' cronjobs yet
    – userlond
    Oct 19, 2015 at 7:22
  • It told me that cron wouldn't run the file because it contains dots in the file name. Thanks!
    – cweiske
    Aug 19, 2021 at 7:26

Wicked cool shell scripts has a shell script that validates crontab files.

You can get the zip archive containing the script here

The script is called verifycron

  • 1
    Link doesn't work anymore as of 11 jan 2017.
    – Epskampie
    Jan 11, 2017 at 11:37
  • Someone fixed the link. In the zip-file it is located in "wicked_cool_shell_scripts_2e-master/6/48-verifycron". Use it with ./48-verifycron /var/spool/cron/crontabs/root to verify your user root crontab-file.
    – MadMike
    May 25, 2021 at 12:08

I found this cool solution here: https://crontab.guru

It doesn't just validate the crontab, it tells you explicitly what and when the crontab will run, and highlights where errors are.


Tailing the logs is the best solution I feel, as pointed out by @mivk in their answer.

journalctl is a good option too:

vedant@zebronics:~$ journalctl -u cron.service 
... <hit shift+G to goto last line>
Nov 03 10:33:01 zebronics cron[627]: (*system*) RELOAD (/etc/crontab)

(Hit shift+G to go the latest line in journal)


This has worked the best for me:

systemctl restart cron; journalctl -u cron --lines 10

Forcing the restart ensures that cron checks the syntax immediately, instead of waiting 60 seconds. If there are any errors, journalctl will show them.


run crontab -T path/to/crontab

If you want to automatically do it before/after, you can write your own visudo style wrapper, such as

$EDITOR /etc/crontab
crontab -T /etc/crontab

Personally, since breaking the crontab is not as bad as breaking sudoers, I think it's fine to just print the message, but you could also everything to a tempfile if you wanted.

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  • 1
    What OS is this valid for? My crontab command on Ubuntu does not have the -T flag at all
    – MightyPork
    Jun 9 at 15:13
  • This is from "cronie" cron by Paul Vixie and Colin Dean. I am on Arch Linux. Info is from my man page. Jun 9 at 18:52

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