Home / ubuntu / Questions / 288626
In Process
mini
Asked: 2013-05-01 08:21:52 +0800 CST

Run two commands sequentially using crontab

  • 772

My 3-year girl loves SuperTux. She can't control the mouse, so the game should run automatically on startup. After the game, the computer should shut down automatically.

However when I put the below command in "crontab -e":

@reboot env DISPLAY=:0.0 /usr/games/supertux2 && echo "PASSWORD" | sudo -S shutdown -h now

The first part runs the game on an old PC at boot time. I expected the second part of the command to turn off the computer when my girl exits the game but it isn't working.

Doesn't the chain-command A && B mean when the A finished, start B?

How can I automate the powering off computer when the game is closed?

startup

1 Answers

  1. Technically, A && B will only execute B when A is successful (exits with status of EXIT_SUCCESS, i.e. 0). Likewise, A || B will only execute B when A fails. Another option could be A; B which should execute B regardless of the exit status of A, but not until A has completed. I don't know how the games is currently exiting, but if it is not exiting with an EXIT_SUCCESS status, then B won't get executed.

    To test this you can run the following commands and see which ones generate the string:

    perl -e 'exit 0' && echo "exit was successful"
perl -e 'exit 0' || echo "exit was successful"
perl -e 'exit 0'; echo "exit was successful"
perl -e 'exit 1' && echo "exit was failure"
perl -e 'exit 1' || echo "exit was failure"
perl -e 'exit 1'; echo "exit was failure"

    Finally, you could create a shell script /usr/games/supertux2.sh:

    #!/bin/sh
/usr/games/supertux2
echo "PASSWORD" | sudo -S shutdown -h now

    And then call that on reboot, rather than /usr/games/supertux2

    • 11