After sudo crontab -e (it wrote "/tmp/crontab.XXXX70pN9h" 1L, 19C 1,1 All

Then I saved the file. And to check..? (how? i don't know)

And to check I 
ps -e | grep cron
29818 ?        00:00:00 cron

So.. but I decided to check again but

sudo cat /etc/cron.hourly
cat: /etc/cron.hourly: Is a directory
xi@localhost ~ $ sudo ls /etc/cron.hourly

Nothing! i.e. in directory

As I understand first 0 in the hour-position means every hour?

  • Ok, I'll wait for an hour (the most lessest gap in documentation)
    – Xsi
    Commented Nov 9, 2012 at 13:17
  • You definitely want to check a question of mine. It has an answer by Stephane Chazelas that explains how you can create an interactive shell that is identical to the environment your cron job will see. If you walk through his little procedure, you get a prompt and you can test your cronjob step by step and see where it fails. unix.stackexchange.com/a/56503/16841 Sure it isn't a 100% match for your question, but it can help you troubleshoot crontab issues.
    – jippie
    Commented Nov 23, 2012 at 22:56

5 Answers 5


The fields in cron are:

m      h       dom             mon     dow          command
Minute Hour    Day of Month    Month   Day of week  <command>

And your 0 * * * * <command> then translates to "Execute command on every hour, every day, every month, and every weekday, if the minute is 0"

You can list your crontab by using crontab -l, as delh already stated.

Take this Link here, there are some Practical Cron Examples

  • date [-u|--utc|--universal] [MMDDhhmm[[CC]YY][.ss]] it's like , But visa versa
    – Xsi
    Commented Nov 9, 2012 at 17:36
  • What does this have to do with cron? Commented Nov 9, 2012 at 19:36

Your crontab and cron.hourly are separate entities. Putting something in your crontab does not put it in cron.hourly, even if it runs every hour. Putting a script in cron.hourly is merely another way of having it run every hour, that is, your cron daemon checks both your crontab and cron.hourly. Having it in both would run it twice.

  • Fri Nov 9 15:16:01 EET 2012 xi@localhost ~ $ ls /var/log/cron.log ls: cannot access /var/log/cron.log: No such file or directory
    – Xsi
    Commented Nov 9, 2012 at 13:21

You can check if the crontab is installed using:

sudo crontab -l

Every hour a log message should appear in /var/log/syslog that it was executed.

Further reading:


I tink that the first zero (0) is the minutes. But if you say you want something done when the minutes is 0 it would be performed every hour. As only once an hour the minutes are zero.


You can simply run a cron by the following tutorial


0 * * * *  /path
  • 1
    Normally we don't really like link-only answers a lot, because links can die over time. Can you reproduce maybe the main steps of the linked page?
    – Bernhard
    Commented Aug 25, 2014 at 7:47

If you are actually looking for user cron files to see when it's changed or something of that nature it can be found at /var/spool/cron/ but you probably shouldn't manipulate the files manually.

  • Not so much probably shouldn't as should not. The cron daemon won't notice changes if you edit the files directly. Instead, use crontab -l to list for the current user, crontab -e to edit for the current user, and/or include -u {user} as well to access that different user's crontab. This is all well defined in the man page for crontab. Commented Oct 27, 2015 at 19:33
  • I believe there are ways to set cron to automatically check the files for changes if you really need to update them manually.
    – Molimo
    Commented Oct 28, 2015 at 16:53
  • If you need to update them manually then use the crontab interface; that's what it's there for. Otherwise you're going to have to stop and restart the cron daemon. Commented Oct 28, 2015 at 18:04

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