Install the Cron Schedule for david user to display “Hello” on daily 5:30.
Login as a root usercat >schedule.txt
30 05 * * * /bin/echo “Hello”
3. crontab -u david schedule.txt
4. service crond restart
The cron system is essentially a smart alarm clock. When the alarm sounds, Linux runs the
commands of your choice automatically. You can set the alarm clock to run at all sorts of regular
time intervals. Alternatively, the at system allows you to run the command of your choice once, at
a specified time in the future.
Red Hat configured the cron daemon, crond. By default, it checks a series of directories for jobs to
run, every minute of every hour of every day. The crond checks the /var/spool/cron directory for
jobs by user. It also checks for scheduled jobs for the computer under /etc/crontab and in the
Here is the format of a line in crontab. Each of these columns is explained in more detail:
#minute, hour, day of month, month, day of week, command
* * * * * command