How to properly modify the sudoers file to create a launcher in order to shutdown the system?

Question

I did it adding the following line, but doesn't work (at least in my case):

username ALL=(ALL) NOPASSWD:/sbin/shutdown -h now

then making a launcher in the desktop with the following instruction:

sudo shutdown -h now

When I tried it, keeps asking me the password. What am I doing wrong?

PS: I'm using visudo

Answer 1

The order of lines in /etc/sudoers is important.

The man page says:

   When multiple entries match for a user, they are applied in order.  Where there are
   multiple matches, the last match is used (which is not necessarily the most specific
   match).

So, if you have the following usual line in your /etc/sudoers file

%admin ALL=(ALL) ALL

and your user is part of the admin group, you need to put the line in your question behind that line. Otherwise it will never be used, because the line for %admin will always match instead.

In general, put the most specific lines (like those for single users and commands) at the end of the file.