Home / ubuntu / Questions / 313095
In Process
mini
Asked: 2013-06-27 12:20:28 +0800 CST

Schedule to turn off monitor via crontab?

  • 772

I want to turn off monitor on a specific period of time automatically (for example between 07:00 and 11:00). Is there any command to be set in crontab file? Is there any better way?

In summary:

Turning off the monitor at 07:00 automatically.

Turning on the monitor at 11:00 automatically.

  • scren-saver & lock screen are disabled!
shutdown

2 Answers

  1. Assuming that you are using the default gnome-screensaver for Ubuntu, open a terminal and run next commands followed by instructions:

    1. mkdir -p bin - this command will make a bin directory in your home folder if you don't already have it.
    2. gedit ~/bin/screen_on_or_off.sh - this will create the new file screen_on_or_off.sh in gedit.

    3. Copy and paste the next script:

      #!/bin/bash

export DISPLAY=:0 #very important if you want to be runned by a cron job

current_hour=$(date +"%k")

# Defining the disable_screensaver function
function disable_screensaver {
    # Disabling sleep time
    # 0 value will never turn the screen off; you can change this value as you wish:
    # for example to turn the screen of after 10 min, use 600
    gsettings set org.gnome.settings-daemon.plugins.power sleep-display-ac 0
    gsettings set org.gnome.settings-daemon.plugins.power sleep-display-battery 0
    gsettings set org.gnome.desktop.session idle-delay 0
}

# Defining the enable_screensaver function
function enable_screensaver {
    # Enabling sleep time to 1 second
    gsettings set org.gnome.settings-daemon.plugins.power sleep-display-ac 1
    gsettings set org.gnome.settings-daemon.plugins.power sleep-display-battery 1
    gsettings set org.gnome.desktop.session idle-delay 1

    notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "Let's go to sleep now!"
}

if [ "$current_hour" -ge "7" ] && [ "$current_hour" -lt "11" ]; then
    enable_screensaver
else
    disable_screensaver
fi

exit 0

    4. Save the file and close it.

    5. Go back into terminal and run: chmod +x screen_on_or_off.sh - to grant execute access for the script.
    6. Just for test, to run your new script, type in terminal ~/bin/screen_on_or_off.sh.

    7. Edit the crontab entries using crontab -e command (by default this will edit the current logged-in users crontab) and add the following line:

      */1 * * * * /home/$USER/bin/screen_on_or_off.sh  #change $USER with your username

      I have set the cron job for every minute, but you can change as you wish or as you think is better. See http://en.wikipedia.org/wiki/Cron in this sense.

    8. Save the file and check the new crontab entry with crontab -l.

    Now your screen will turn off every day between 7 and 11.

    • 4

  2. Newer and much simpler answer, put this in cron:

    0 07 * * *  export DISPLAY=:0 && xset dpms force off
0 11 * * *  export DISPLAY=:0 && xset dpms force on
    • 3