Is crontab a daemon?
The cron daemon ( crond ) is a system-managed executable that runs in memory with which users may schedule tasks. The user command to work with the cron service is crontab (cron table). Any user may schedule cron tasks or jobs on a system. The task runs under the user account from which it was created.
Which daemon should be running so we can use crontab?
The crond daemon is the background service that enables cron functionality. The cron service checks for files in the /var/spool/cron and /etc/cron. d directories and the /etc/anacrontab file. The contents of these files define cron jobs that are to be run at various intervals.
What do you need to know about crontab?
DESCRIPTION. crontab is the program used to install, deinstall or list the tables used to drive the cron daemon in Vixie Cron. A crontab file contains instructions to the cron daemon of the general form: “run this command at this time on this date”.
How does the cron daemon work in Linux?
The Cron daemon is a built-in Linux utility that runs processes on your system at a scheduled time. Cron reads the crontab (cron tables) for predefined commands and scripts. By using a specific syntax, you can configure a cron job to schedule scripts or other commands to run automatically.
When does Cron send output to the owner of crontab file?
Output (Optional) By default, cron sends an email to the owner of the crontab file when it runs. This is a convenient way to keep track of tasks. Keep in mind that regular or minor tasks can fill up your inbox quickly.
Can a root user use a cron job?
If cron.deny exists and is empty, all users can use crontab. If neither file exists, only the root user can use crontab. The cron.allow and cron.deny files consist of one username per line. By default, cron jobs cause an email to get sent to the user executing the command in crontab.