sudo rm somefile
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I won't get into how much this is a bad idea; simply put, running
sudoin crontab requires your password to be stored somewhere in plaintext.
It's a bad idea.
The following is the preferred method of running administrative tasks through cron. Since you don't really need to write
sudo in the crontab, if you are modifying root's crontab.
Run the following command:
sudo crontab -e
This opens up
sudo is not necessary to run your command in this context, since it'll be invoked as
Therefore, you would simply append the following to root's crontab.
@hourly rm somefile
Now, if you absolutely want to be unsafe and take risks with your password, the following will run your command from your own crontab, and enter your password automatically when prompted by
Again, this is not recommended.
In your own crontab, write your command like so:
@hourly echo "password" | sudo -S rm somefile
The obvious disadvantage here is that, should anyone ever access your crontab, your password will be readable in plaintext.
You shouldn't do this.
Sometimes it is necessary for root to execute a command as a specific user of the system. For example, with borgbackup, it is common to have root check the warehouse using the borg user. if the task must be executed once a day, we will use the /etc/cron.daily folder, like that:
# cat /etc/cron.daily/borgbackup_check #!/bin/bash sudo -u borg borg check /borgbackup >> /var/log/borgbackup.log
where "-u borg" is used take the identity of the borg user, "borg" is the borg command and "/borgbackup" is the wharehouse.
Nobody mentioned having an executable script with setuid bit? I can see where this might be a security vulnerability, too (don't cut yourself, sharp knives in this drawer, keep permissions tight), but feels less dicey than working in the root crontab. For instance, I'd like to defrag/fstrim nightly or weekly even when I am not present.
Another alternative is to leave a script running in a loop, sleeping until the time is right, that you launch with sudo.