linux scheduled task set manner

The first species: edit crontab configuration file

vim /etc/crontab

Added directly to the file inside

The second: the direct command to view, edit,

View: crontab -l

Edit: crontab -e

usage: crontab [-u user] file
crontab [-u user] [ -e | -l | -r ]
(default operation is replace, per 1003.2)
-e (edit user's crontab)
-l (list user's crontab)
-r (delete user's crontab)
-i (prompt before deleting user's crontab)
-s (selinux context)