The main crontab file /etc/crontab should NEVER be edited manually; you don't want crond to fail.

• The main crontab file /etc/crontab should NEVER be edited manually; you don't want crond to fail.

• Construct a crontab: as root, in /etc/cron.d; as a user, in /var/spool/cron

• A user crontab file can be created by using the standard editor (vi) to create a plain text file with proper crontab fields as above, or using the crontab command

• It is recommended to name the file something distinctive (e.g. allisor.cron) and for it to be stored in your home directory.

• The crontab file can then be submitted to the cron daemon using the crontab command.

• The crontab command can also be used to add, edit, list, and remove individual crontab files submitted previously.