crontab - maintain crontab files for individual users.
Schedule a job for a specific time ( 20th june 06:00 AM):
00 06 20 06 * /home/joe/backup.sh
Schedule a job to run twice a day (10 AM and 5 PM):
00 10,17 * * * /home/joe/backup.sh
Schedule a job for specific range of time (09 AM to 06 PM):
00 09-18 * * * /home/joe/remove_tmp.sh
Schedule a job every weekday (06 AM every Mon, Tue, Wed, Thu and Fri ):
00 06 * * 1-5 /home/joe/backup.sh
Schedule a job for every 5 minutes:
*/5 * * * * /home/joe/save-logs.sh