Scheduling Jobs

Updated Mar 27, 2021 ·

Tasks

1. Ensure systemd timer cleans up the tmp files..
2. Run a cron job that will issue the command "touch /tmp/cronfile" 5 minutes from now.
3. Use at to schedule a job to power off your system at a convenient time laer today.

Solution

1. Systemd timer cleans up the tmp files

Check if the systemd-tmpfiles-clean timer is enabled

sudo systemctl status systemd-tmpfiles-clean.timer

Enable the timer if it is not already enabled

sudo systemctl enable systemd-tmpfiles-clean.timer
sudo systemctl start systemd-tmpfiles-clean.timer

Verify the timer is active

sudo systemctl status systemd-tmpfiles-clean.timer

2. Run a scheduled crob job

Run a cron job that will issue the command below 5 minutes from now.

touch /tmp/cronfile

Open the crontab editor

crontab -e

Add the following line to schedule the cron job

# (Replace `date` and `time` with the current time plus 5 minutes)
MM HH DD MM * touch /tmp/cronfile

Where:

• MM is the minute (current minute + 5)
• HH is the hour
• DD is the day of the month
• MM is the month

For example, if the current time is 14:00, the line would look like this:

05 14 * * * touch /tmp/cronfile

Save and exit the editor.

3. Schedule power off using at

Install at if it is not already installed

sudo yum install at
sudo systemctl enable atd
sudo systemctl start atd

Schedule the power-off job

echo "sudo poweroff" | at HH:MM

Replace HH:MM with the time you want to power off the system. For example, to power off at 10:30 PM:

echo "sudo poweroff" | at 22:30