crontab

(see this site)for further details)

Cron Tab syntax :-
A crontab file has five fields for specifying day , date and time  followed by the command to be run at that interval.

 *   *   *   *   *  command to be executed
 |   |   |   |   |
 |   |   |   |   +---- day of week (0{$_SERVER['DOCUMENT_ROOT']}/sickingfamily/-6) (Sunday=0)
 |   |   |   |
 |   |   |   +---- month (1-12)
 |   |   |
 |   |   +---- day of month (1-31)
 |   |
 |   +---- hour (0-23)
 |
 +----min (0-59)

* in the value field above means all... legal values as in braces for that column.
The value column can have a * or a list of elements separated by commas. An element is either a number in the ranges shown above or two numbers in the range separated by a hyphen (meaning an inclusive range).

Note: The specification of days can be made in two fields: month day and weekday. If both are specified in an entry, they are cumulative meaning both of the entries will get executed .