15

In a cron expression, what is the difference between 0/1, 1/1 and * ?

  • The / is stepping, explained really well here: publib.boulder.ibm.com/infocenter/db2luw/v9r5/index.jsp?topic=/… – NickW Mar 19 '14 at 12:36
  • 1
    Why the down vote, please? Any missing information? Does the question belong to another stackexchange site? – sdabet Mar 19 '14 at 12:47
  • Mouse over the down arrow; the popup says "This question does not show any research effort; it is unclear or not useful". Downvotes without comment may be presumed to be for at least one of those reasons - though I note the downvoter has since retracted. – MadHatter supports Monica Mar 19 '14 at 14:33
  • Thanks @MadHatter, I just don't have enough reputation yet to see the vote details – sdabet Mar 19 '14 at 15:55
20

It depends on where the terms are located

  • 0/1 means starting at 0 every 1.
  • 1/1 means starting at 1 every 1.
  • * means all possible values.

so

  • For the minutes, hours, and day of week columns the 0/1 and * are equivalent as these are 0 based.

  • For the Day Of Month and Month columns 1/1 and * are equivalent as these are 1 based.

  • Does it make any sense to use 0/1 for months then? What would happen? – sdabet Apr 25 '15 at 5:26
4

In crontab definition, the meaning of the five date/time fields are :

  1. At which minutes of the hour (so from 0 to 59)
  2. At which hour of the day (so from 0 to 23)
  3. At which day of the month (so from 1 to 31)
  4. At which month of the year (so from 1 to 12 or names - Jan, Feb, ...)
  5. At which day of the week (so from 0 to 6 or names - Sun, Mon, ...)

A * means from the first to the last element of the range. A n/x means starting at n, at every x values.

In your case, this can be translated by :

  1. At minutes 0
  2. Starting at midnight, every hour (which is similar to *)
  3. Each day of the month
  4. Starting the first month (January), every month (which is similar to *)
  5. Each day of the week (for the first *)

The end looks incorrect (? *) as it is in the place of the command. Or in the place of the username & command if taken from a file under /etc/cron.d/ and not from the crontab of a specific user.

0

The 0/1 means every 1 min or every mintue and 1/1 means evey month i think,but i m not sure it will work that way for month.

  • Then what is the difference between 0/1, 1/1 and * ? – sdabet Mar 19 '14 at 12:38
  • The 0/1 is in the hour position. – user9517 supports GoFundMonica Mar 19 '14 at 12:42
  • that one is for hour – vic Mar 19 '14 at 12:42
  • Sure, but can I replace the hour part 0/1 by 1/1 for instance ? Will it mean the same? – sdabet Mar 19 '14 at 12:45
  • Isn't the same as putting 0 or 1 then ? – sdabet Mar 19 '14 at 12:52

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.