How to shutdown ubuntu server from shell script?

Question

I wrote a simple shell script to shutdown an ubuntu server. Then I created a cron job to execute this script at 23:59 everyday.

#!/bin/bash
sudo shutdown -h now

I got this error message:

sudo: no tty present and no askpass program specified

when I removed the sudo from the code, I got a different error message:

/home/qinking126/scripts/test.sh: line 3: shutdown: command not found

How do I resolve this?

Solution

Make sure the cron script is executable and also running as root, and replace shutdown by its full path given to you by:

command -v shutdown

On Ubuntu GNU/Linux (and GNU/Linux in general), it should be /sbin/shutdown :

#!/bin/bash
/sbin/shutdown -h now

Note that adding a file named like /etc/cron.d/midnight-shutdown and containing:

59 23   * * *   root    test -x /sbin/shutdown && /sbin/shutdown -h now

should do what you want without the overhead of a full bash script. Here is the code to install this quickly:

echo '59 23 * * *   root    test -x /sbin/shutdown && /sbin/shutdown -h now' \
    | sudo tee '/etc/cron.d/midnight-shutdow'
sudo service cron reload

EDIT: To reply to your comment, another possibility of setting is:

echo '59 23 * * *   test -x /sbin/shutdown && /sbin/shutdown -h now' \
    | sudo tee '/etc/cron.d/midnight-shutdown'
sudo service cron reload

It is quite strange that cron print you this error message.

Comments

[qinking126]

got this error message "/bin/sh: 1: root: not found"

[Biapy]

added another setting possibility.