Crontab Format

gistfile1.txt

crontab: command used to schedule and run tasks in the background at defined regular intervals.

Format:
   *   *    *   *   *   *
( MIN HOUR DOM MON DOW CMD )

where: 

MIN- minute -0-59

HOUR-hour-0-23

DOM-Date of Month-1-31

MON- Month of year-1-12

DOW-Day of week-0-6

CMD-command- Any command to execute

After logging into the server, write command the below given command:
crontab -e
It will prompt you to edit thus edit/add  your desired schedule for a file to be executed.


Few examples are mentioned below:

To execute  a cron in every minute:   * * * * * CMD
Example: * * * * * /path-of -file-to-be-executed
To execute a cron for particular time: (say every hour between 9 AM to 6 PM everyday)
Example: 0 9-18 * *  * /path-of-file-to-be-executed
 To execute a cron on particular day of the week:(say each monday at 10 AM and 6 PM)
Example: 0 10,18 * * Mon /path-of-the-file-to-be-executed
To execute a cron on particular date  and time:(say Nov 15 at 10:15 AM)
Example: 15 10 15 11 * /path-of-the-file-to-be-executed
To execute a cron on every 10 minutes:
Example: */10 * * * * /path-of-the-file-to-be-executed