Cron submission of tasks | cron important configure files and directory

/var/spool/corn/username file it contain each user regulates his distinguished file and this is used in the UNIX system five
/etc/crontab file. These file it is accessible only by the root. crontab file from BSD Unix and it is derivatives.
/etc/cron.d directory. It is similar to crontab file. Only root user has permission to access the files.
/etc/cron.hourly
/etc/cron.daily
/etc/cron.weekly
/etc/cron.monthly these are the directory all these files are shell script which run time indicated in /etc/crontab file. Only root use has permission to access the files.

Cron daemon Linux task scheduling |cron tables fields | /etc/cron.allow and /etc/cron.deny

Cron command similar to the task scheduling “at” Linux command. Cron it performs the task can scheduled to run without being attended. It is component of vixiecron rpm packages and it permits more flexibility in automation of execution in command. If the user who did not perform the task automation then it face error message or output are emailed to the user.
Cron Access control files
/etc/cron.allow->list of user access submitting task
/etc/cron.deny->list of user deny submitting task
Cron tables
Cron daemon is suited for recurring task as it will use configuration files called cron tables.
It contains six fields. Five fields are times for running the command and the sixth field is the complete the path name to the shell script.