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Eka
Asked: 2015-05-19 10:22:38 +0800 CST

How to execute a shutdown with timer and screensaver command in a script

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I made this script when executed will shutdown my system (after some time) and should enable a screensaver.

#!/bin/bash
sudo shutdown -h +30
gnome-screensaver-command -a

There are mainly two problems in this script.

  1. It asks for password (which I don't want)
  2. After executing sudo shutdown -h +30 its not running gnome-screensaver-command -a

that is, it activates shutdown but not the screensaver

How to solve these problem?

command-line

2 Answers

  1. Best Answer

    Solution to problem 1 and 2:

    1. You need to edit your /etc/sudoers (sudo visudo) file to add the relevant entry to grant the passwordless sudo permission for the user to run this script (not the shutdown command) :

      foo spamegg = (root) NOPASSWD: /path/to/script.sh

      Here foo is the username, spamegg is the hostname, replace the /path/to/script.sh accordingly. Now run the command as (make the script executable):

      sudo /path/to/script.sh

      Note that the gnome-screensaver-command -a command will also run as root, if you don't want that you need to grant the permission for passwordless sudo shutdown command for the user:

      foo spamegg = (root) NOPASSWD: /sbin/shutdown

    2. The second problem is due to the fact that in your current script the gnome-screensaver-command -a will only run after the completion of shutdown command. As the shutdown command will actually be executed after 30 minutes, hence its in a blocking state. To solve this you can put the shutdown command in the background :

      shutdown -h +30 &
gnome-screensaver-command -a

    In a nutshell, you can make the script as following :

    #!/bin/bash
shutdown -h +30 &
gnome-screensaver-command -a

    Run it as :

    sudo /path/to/script.sh

    Before using sudo, store the script in a secure place, it must only be accessible to you and you must be sure of the contents of the script.

    • 6

  2. When you have two commands on two separate lines of a shell script, the second will only run when the first has finished. To avoid this, you need to add a & to the end of the first command to have it run in the background:

    #!/bin/bash
sudo shutdown -h +30 &
gnome-screensaver-command -a

    As for not asking for the password, you'll need to tell sudo that your user has the right to run /sbin/shutdown with no password. Run sudo visudo and add this line to /etc/sudoers:

    eka  ALL=NOPASSWD:/usr/sbin/shutdown

    Change eka to whatever your username is. Save the file and you will now be able to run sudo shutdown without being prompted for a password.

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