questions about sudo

stu_mueller · 04-04-2008, 08:02 AM

I have a couple of questions regarding sudo. I have read the man pages, and am still a bit confused

if I add

stuart ALL=NOPASSWORD: ALL to sudoers I can run any command but would have to prefix it with sudo so: 'sudo /fullpath/file'?

if I specify

stuart ALL=NOPASSWORD: /sbin/shutdown i would need to type 'sudo /sbin/shutdown'? or could I just type 'sudo shutdown'?

could I specify shutdown parameters or would they need to go in sudoers as well (stuart ALL=NOPASSWORD: /sbin/shutdown -h now)?

in all cases I would need to prefix the command with sudo?

If I wanted to chmod rc.bluetooth to make it executable and then run it would I just need sudo permissions to chmod or would I need sudo permissions to run rc.bluetooth as well?

In your experience is it best to add commands to sudoer as I find I need them or just specify ALL. (The problem with ALL is that I figure I may as well log in as root!)

Stuart

mahmoud · 04-04-2008, 08:23 AM

basically any command you can issue as root u can with the sudo in front eg
sudo halt
sudo restart
sudo vim /etc/apache
sudo /etc/init.d/apache2 restart

Bruce Hill · 04-04-2008, 09:14 AM

Setup sudo by issuing in a terminal as root "vigr" first and add your
normal user to the wheel group. It should look like this:

Code:

wheel:x:10:root,stuart

Then setup sudo by issuing "visudo" and uncomment this line:

Code:

# %wheel ALL=(ALL)       NOPASSWD: ALL

You will be using the editor vi, and might not be familiar with it. So
let me make it simple just to get you setup.

After you issue "vigr" press the I key or press Insert and move the cursor
to the end of the wheel group line. Then type a , then your username. Then
to close the vi editor, press Esc and then :wq (semi-colon then w then q)
which means write and quit. Then for the "visudo" you can simply move the
mouse cursor to the # in the front of that line and then press x which will
remove the # then :wq

After that is done, as a normal user you can enter "sudo -i" in a terminal
and you will su to root and his home directory with his environment variable.
From there you _are_ root, and issue commands as root.

And you can issue any command that is in your normal users $PATH just by adding
sudo in front of it as stated above. However, if the command is not in your
normal users $PATH, you will have to give the full path to the command. To see
what path a user has, as that user in a terminal type $PATH and press Enter.

For instance, you would need the full path to shutdown, i.e. "sudo /sbin/shutdown -h now"

After experimenting with things similar to what you posted, this seemed to me
to be the easiest way to set it up.

rworkman · 04-04-2008, 10:41 AM

Quote:

Originally Posted by mahmoud

basically any command you can issue as root u can with the sudo in front eg
sudo halt
sudo restart
sudo vim /etc/apache
sudo /etc/init.d/apache2 restart

While your comment is not necessarily *wrong* - it needs some elaboration to be completely correct. Unlike some other distributions, Slackware leaves setup of sudo to the administrator of the computer - we don't install a "magic hammer" by default.

rworkman · 04-04-2008, 10:45 AM

Quote:

Originally Posted by Bruce Hill

And you can issue any command that is in your normal users $PATH just by adding sudo in front of it as stated above. However, if the command is not in your normal users $PATH, you will have to give the full path to the command. To see what path a user has, as that user in a terminal type $PATH and press Enter.

For instance, you would need the full path to shutdown, i.e. "sudo /sbin/shutdown -h now"

Good advice indeed about PATH issues with sudo.

Two ideas to address those (either of which works just fine, but depending on your planned usage of sudo, one is better than the other):

In /etc/profile.d/10-local.sh (create that file, as it doesn't exist, and also make it executable), put this (adjust username as appropriate):

Code:

if [ "$USER" = "rworkman" ]; then
  export PATH="${PATH}:/usr/sbin:/sbin"
fi

Alternatively, create some aliases:

Code:

if [ -e $HOME/.logout ]; then
  alias "reboot=. $HOME/.logout ; sudo /sbin/shutdown -r now"
  alias "halt=. $HOME/.logout ; sudo /sbin/shutdown -h now"
else
  alias "reboot=sudo /sbin/shutdown -r now"
  alias "halt=sudo /sbin/shutdown -h now"
fi

stu_mueller · 04-04-2008, 03:49 PM

Thanks Guys,

I think I have the sudo figured out now.

what I'm trying to do is write a script that will chmod a+x rc.bluetooth and start it, then bring up my hci0 interface and finally start kbluetooth

I have this working!

I then have a second script that takes down hci0, runs rc.bluetooth stop and then chmod a-x rc.bluetooth

Again this is working. What I would like to do is combine the scripts. have it check for the existence of kbluetooth in the process list (which I think I can do) and if it doesn't exist do the startup procedure, if it dows exist run the stop procedure.

The only bit I am not sure on is how to kill off kbluetooth, the most obviuos way is to say 'killall -e /usr/bin/kbluetooth'

but is that a safe way to close the application, or is there a better way? from the gui I can choose quit, but the command line doesn't give me that option. I don't know whether killing a process is hte best way of performing an exit?