CRON

Format of crontab:

First five fields are:

<minutes:0-59> <hours:0-23> <day-of-month:1-31> <month:1-12> <day-of-week:0-6:0=Sunday>

Command: sudo crontab -e

Alternatively:

echo "* 12 * * * /usr/local/bin/script" >> /var/spool/cron/root