Hello,

May i ask that:
#1: How-to edit '/etc/sudoers'(aka 'sudo' Policy) file if:
The 'root' user want a nonRoot user 'bh0laJi' to be able to execute "/bin/shutdown -h now" and a script '/bin/rdshft.sh', and nothing else as 'sudo'.

#2: What does each of the 'ALL' in "ALL=(ALL:ALL) ALL" mean?

Distribution: Debian+, ArchLinux...

Thanking you...

edit sudo with visudo and test your results at once.
Plenty of examples online. It's very fussy on syntax, spacing, etc.

Very carefully.

In all seriousness, do remember to test your changes in another window before closing your editor session.

The manual page for sudoers is a bit overwhelming, see "man sudoers" anyway. In ALL=(ALL:ALL), the first part before the equal sign refers to the FQDN of the systems in question. The parts inside the parenthesis are the use and group one may switch to. Often people write (ALL:ALL) when they really mean (root:root) instead.

You might look at the second edition of sudo Mastery by Michael W Lucas for an excellent explanation of all the capabilities. He also did a presentation which is preserved in Youtube as sudo: You're Doing It Wrong, along with accompanying slides somewhere. However the book is better.

Then for your first question:

Try something like the following:

The percentage sign means that the group is targeted and not just the one account. It makes debugging easier in many cases. Then the empty quotes after the script name mean that the account is not allowed to send parameters to it and must run it without them. If you want the group to be able to run many forms of shutdown, then leave off the options. Without any options and without the empty quotes, any and all options are allowed.

An instantaneous shutdown might not be most appreciated on a multi-user system.

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Three ways exist to edit the sudoers file:

1) visudo
2) sudoedit
3) plain text editor, which I would strongly discourage unless you know what you're doing

I personally am in the habit of using sudoedit because I have a list of text files specified as needing privileged access to modify and sudoedit does the job nicely, without having to switch between apps.

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