crontab
ShellPackage: cron
Edits an account's table of scheduled jobs. On a systemd machine a timer does the same with a log, a status and catch-up of missed runs — crontab is what you will find on existing machines.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
crontab -e- Edits the current user’s crontab.
crontab -l- Prints the crontab without opening an editor.