> For the complete documentation index, see [llms.txt](https://openai.gitbook.io/code-cheatsheets/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://openai.gitbook.io/code-cheatsheets/all/bash/cron.md). # Cron Apparently you can schedule a file to run with `cron` command natively in bash :0 0 wget -O - -q -t 1 ```php # +---------------- minute (0 - 59) # | +------------- hour (0 - 23) # | | +---------- day of month (1 - 31) # | | | +------- month (1 - 12) # | | | | +---- day of week (0 - 6) (Sunday=0) # | | | | | * * * * * command to be executed ``` If you computer is off when it was supposed to be run, doesn't run it `anacrontab` apparently can run these jobs after the fact ## Other cron syntax ``` * * * * * * ┬ ┬ ┬ ┬ ┬ ┬ │ │ │ │ │ │ │ │ │ │ │ └ day of week (0-7)(0/7 = Sun) │ │ │ │ └───── month (1 - 12) │ │ │ └────────── day of month (1 - 31) │ │ └─────────────── hour (0 - 23) │ └──────────────────── minute (0 - 59) └───────────────────────── second (0 - 59, OPTIONAL) ``` | Operator | Purpose | Example | | ----------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | asterisk ( \* ) | Specifies all possible values for a field | An asterisk in the hour time field is equivalent to “every hour.” | | question mark (?) | A question mark ( ? ) is allowed in the day-of-month and day-of-week fields. It is used to specify “no specific value,” which is useful when you need to specify something in one of these two fields, but not in the other. | If you want a trigger to fire on a particular day of the month (for example, the 10th), but you don't care what day of the week that is, enter 10 in the day-of-month field, and ? in the day-of-week field. | | dash ( - ) | Specifies a range of values | 2-5, which is equivalent to 2,3,4,5 | | comma ( , ) | Specifies a list of values | 1,3,4,7,8 | | slash ( / ) | Used to skip a given number of values | */3 in the hour time field is equivalent to 0,3,6,9,12,15,18,21. The asterisk (* ) specifies “every hour,” but the /3 means only the first, fourth, seventh.You can use a number in front of the slash to set the initial value. For example, 2/3 means 2,5,8,11, and so on. | | L (“last”) | The L character is allowed for the day-of-month and day-of-week fields.Specifies either the last day of the month, or the last *xxx* day of the month. | The value L in the day-of-month field means “the last day of the month,” which is day 31 for January, or day 28 for February in non-leap years. If you use L in the day-of-week field by itself, it simply means 7 or SAT. But if you use it in the day-of-week field after another value, it means “the last *xxx* day of the month.” For example, 6L means “the last Friday of the month.”*HINT:*When you use the L option, be careful not to specify lists or ranges of values. Doing so causes confusing results. | | W (“weekday”) | The W character is allowed for the day-of-month field.Specifies the weekday (Monday-Friday) nearest the given day. | If you specify 15W as the value for the day-of-month field, the meaning is “the nearest weekday to the 15th of the month.” So if the 15th is a Saturday, the trigger fires on Friday the 14th. If the 15th is a Sunday, the trigger fires on Monday the 16th. If the 15th is a Tuesday, it fires on Tuesday the 15th. However, if you specify 1W as the value for day-of-month, and the 1st is a Saturday, the trigger fires on Monday the 3rd, because it does not “jump” over the boundary of a month’s days. The W character can only be specified when the day-of-month is a single day, not a range or list of days.*HINT:*You can combine the L and W characters for the day-of-month expression to yield LW, which translates to “last weekday of the month.” | | pound sign ( # ) | The pound sign ( # ) character is allowed for the day-of-week field. This character is used to specify “the nth” *xxx* day of the month. | The value of 6#3 in the day-of-week field means the third Friday of the month (day 6 = Friday and #3 = the 3rd one in the month).*Other Examples:* 2#1 specifies the first Monday of the month and 4#5 specifies the fifth Wednesday of the month. However, if you specify #5 and there are fewer than 5 of the given day-of-week in the month, no firing occurs that month. |