cron is a unix, solaris utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon. These tasks are often termed as cron jobs in unix , solaris.
Crontab (CRON TABle) is a file which contains the schedule of cron entries to be run and at specified times.
To edit your crontab use:
crontab -e
The format of the crontab file is as follows:
Minute (0-59) Hour (0-23) Day of Month (1-31) Month (1-12 or Jan-Dec) Day of Week (0-6 or Sun-Sat) Command