Editing crontab [duplicate]

You should note that the reason you got an error specifying that the file is read-only is because you are trying to edit a root owned file without being root.

If you want to edit /etc/crontab you should execute your editor as root - (e.g. sudo vi /etc/crontab). Note that it isn't the recommended way for regular users

The answer in here suggest using crontab -e in order to edit the crontab file.

Note that /usr/bin/crontab is executed as root (set user-id root), and will allow you edit crontab for your own user - the file will be created in this root owned folder /var/spool/cron/crontabs.

If you want to execute crontab services which will run as root You should use sudo in order to became root.

You can either update /etc/crontab directly by using sudo vi /etc/crontab (or use any other text editor) and add a line for your job specifying the user as root...

Or you can run:

sudo crontab -e

Which will edit root's crontab file in /var/spool/cron/crontabs.