Crontab in Shell-Scripting

Crontab is a utility that enables user to schedule tasks to run at specific time or intervals. Like backing up the files, running system maintenance or sending email reports.
Cron uses a daemon called cron to execute the scheduled tasks.

Some crontab commands:

crontab -e:Used to edit the crontab

crontab -l: Used to view your current cronjob.

crontab -r: Used to delete cronjob

#Format of using crontab: ***** /usr/bin/python3 /path/to/task.py
Here, /usr/bin/python3 is used to execute the /path.to/task.py

Also, ***** denotes minutes, hour, day(month), month, day(week)

For example, 15 14 *** denotes the crontab will publish the cronjob in 2:15 pm.
Also, @reboot, @daily and many others can also be used in place of *****.