In crontab does the Day of the Week field run from 0 - 6 or 1 -7?
I am seeing conflicting information on this. wikipedia states 0-6 and other sites I have seen are 1-7.
Also what would be the implication or either using 0 or 7 incorrectly? i.e. would the cron still run?
0 and 7 both stand for Sunday, you can use the one you want, so writing 0-6 or 1-7 has the same result.
Also, as suggested by @Henrik, it is possible to replace numbers by shortened name of days, such as MON, THU, etc:
0 - Sun Sunday 1 - Mon Monday 2 - Tue Tuesday 3 - Wed Wednesday 4 - Thu Thursday 5 - Fri Friday 6 - Sat Saturday 7 - Sun Sunday Graphically, * * * * * command to be executed stands for:
| minute | hour | day of month | month | day of week | |
|---|---|---|---|---|---|
| (0-59) | (0-23) | (1-31) | (1-12) | (1-7) | |
| * | * | * | * | * | command to be executed |
Or using the old style:
┌────────── minute (0 - 59) │ ┌──────── hour (0 - 23) │ │ ┌────── day of month (1 - 31) │ │ │ ┌──── month (1 - 12) │ │ │ │ ┌── day of week (0 - 6 => Sunday - Saturday, or │ │ │ │ │ 1 - 7 => Monday - Sunday) ↓ ↓ ↓ ↓ ↓ * * * * * command to be executed Finally, if you want to specify day by day, you can separate days with commas, for example SUN,MON,THU will exectute the command only on sundays, mondays on thursdays.
You can read further details in Wikipedia's article about Cron and check a cron expression online with crontab.guru.
Sat-Sun, only 6-7 or Sat,Sun
SUN, Sun, Sunday in your response
:-) Sunday | Sun -> 0 | Monday | Mon -> 1 Tuesday | Tue -> 2 Wednesday | Wed -> 3 Thursday | Thu -> 4 Friday | Fri -> 5 Saturday | Sat -> 6 | :-) Sunday | 7 As you can see above, the numbers 0 and 7 are both assigned to Sunday. There are also the English abbreviated days of the week listed, which can also be used in the crontab.
Examples of Number or Abbreviation Use
15 09 * * 5,6,0 command 15 09 * * 5,6,7 command 15 09 * * 5-7 command 15 09 * * Fri,Sat,Sun command The four examples do all the same and execute a command every Friday, Saturday, and Sunday at 9.15 o'clock.
In Detail
Utilising both 0 and 7 to represent Sunday is advantageous for creating weekday ranges[*] that start or end with Sunday, such as 0-2 or 5-7. Ranges must start with the lower number and finish with the higher number. Abbreviations like Sun, Mon, Tue, etc. can also be used. But Sun is not allowed to be set at the end of the range. For example, you cannot shorten Fri,Sat,Sun to Fri-Sun.
[*] In the context of a crontab, a range is used to specify a continuous sequence of time units, such as minutes, hours, days, or weekdays. Ranges in crontab are represented using a hyphen-minus character (-) between the lower and upper bound values. For instance, a range of weekdays from Monday (1) to Wednesday (3) would be represented as 1-3.
Fri,Sat,Sun can’t be shortened to Fri-Sun.
Sun is handled like 0, it can only be placed at the beginning as the first day. If you want to set Sunday as the last day, you can use the numbers and use 7 for Sunday.You can also use day names like Mon for Monday, Tue for Tuesday, etc. It's more human friendly.
