To learn more about configuring automated tasks, refer to the
cron man page — overview of
crontab man pages in sections 1 and 5
— The man page in section 1 contains an overview of the
crontab file. The man page in section 5
contains the format for the file and some example entries.
/usr/share/doc/at-<version>/timespec contains more
detailed information about the times that can be specified for cron
at man page — description of
at and batch and
their command line options.