How to run crontab job every week on Sunday

Question

Here is an explanation of the crontab format.

# 1. Entry: Minute when the process will be started [0-60]
# 2. Entry: Hour when the process will be started [0-23]
# 3. Entry: Day of the month when the process will be started [1-28/29/30/31]
# 4. Entry: Month of the year when the process will be started [1-12]
# 5. Entry: Weekday when the process will be started [0-6] [0 is Sunday]
#
# all x min = */x

So according to this your 5 8 * * 0 would run 8:05 every Sunday.

To have a cron executed on Sunday you can use either of these:

5 8 * * 0
5 8 * * 7
5 8 * * Sun

Where 5 8 stands for the time of the day when this will happen: 8:05.

In general, if you want to execute something on Sunday, just make sure the 5th column contains either of 0, 7 or Sun. You had 6, so it was running on Saturday.

The format for cronjobs is:

 +---------------- minute (0 - 59)
 |  +------------- hour (0 - 23)
 |  |  +---------- day of month (1 - 31)
 |  |  |  +------- month (1 - 12)
 |  |  |  |  +---- day of week (0 - 6) (Sunday=0 or 7)
 |  |  |  |  |
 *  *  *  *  *  command to be executed

You can always use crontab.guru as a editor to check your cron expressions.

Following is the format of the crontab file.

{minute} {hour} {day-of-month} {month} {day-of-week} {user} {path-to-shell-script}

So, to run each sunday at midnight (Sunday is 0 usually, 7 in some rare cases) :

0 0 * * 0 root /path_to_command

The crontab website gives the real time results display: https://crontab.guru/#5_8_*_*_0

When specifying your cron values you'll need to make sure that your values fall within the ranges. For instance, some cron's use a 0-7 range for the day of week where both 0 and 7 represent Sunday. We do not(check below).

Seconds: 0-59
Minutes: 0-59
Hours: 0-23
Day of Month: 1-31
Months: 0-11
Day of Week: 0-6

reference: https://github.com/ncb000gt/node-cron

I think you would like this interactive website, which often helps me build complex Crontab directives: https://crontab.guru/