.What daemon is used for scheduling of the commands?

The crontab command is used for scheduling of the commands to run at a later time.
SYNTAX
crontab [ -u user ] file
crontab [ -u user ] { -l | -r | -e }
Options
-l List – display the current crontab entries.
-r Remove the current crontab.
-e Edit the current crontab using the editor specified by the VISUAL or EDITOR environment variables.
When user exits from the editor, the modified crontab will be installed automatically. Each user can have their own crontab, and though these are files in /var, they are not intended to be edited directly.
If the –u option is given than the crontab gives the name of the user whose crontab is to be tweaked. If it is given without this then it will display the crontab of the user who is executing the command.