crontab example

crontab

# Example of job definition:
# .---------------- minute (0 - 59)
# |  .------------- hour (0 - 23)
# |  |  .---------- day of month (1 - 31)
# |  |  |  .------- month (1 - 12) OR jan,feb,mar,apr ...
# |  |  |  |  .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat
# |  |  |  |  |
# * * * * * user-name command to be executed
#
# Aliases:
# string         meaning
# ------         -------
# @reboot        Run once, at startup.
# @yearly        Run once a year, "0 0 1 1 *".
# @annually      (same as @yearly)
# @monthly       Run once a month, "0 0 1 * *".
# @weekly        Run once a week, "0 0 * * 0".
# @daily         Run once a day, "0 0 * * *".
# @midnight      (same as @daily)
# @hourly        Run once an hour, "0 * * * *".

# Examples:
#
# Every 5 Minutes:
# */5 * * * * foobar

# Backup all mySQL 2:15 am per day.
15 2 * * * root mysqldump -u root -pPASSWORD --all-databases | gzip > /mnt/disk2/database_`date ' %m-%d-%Y'`.sql.gz 

Every three hours 0 */3 * * * foobar