Shell Programming and Scripting

hi guys

a customer asked me to create a menu for linux he also asked me to do this:

open like a command like where a user can execute commands...so for this the users have sudo enabled

the code below works OK.

But it has an issue when a command is executed but the command does not need sudo


like for instance

Code:

cd /
sudo: cd: command not found

how can I allow a user to execute all commands when a command does not need sudo

Code:

echo -e "Press Control+C to finish"
#echo -e " "
while true;
  do
  read whichcmd?"Insert Command: "
  sudo $whichcmd
done

thanks a lot

"cd" is almost useless as an external command, it should be done by the running shell itself.

You have to check the kind of command, some are external files like /usr/bin/who, others, cd for example, are shell builtins.
try this in ksh or bash:

Code:

alias plpl='ls *'
type cd
type who
type plpl

You can use type to differentiate between things sudo can and cannot do.
BTW: if you grant sudo to that user for everything, you have given him/her complete control of the box. There is a file, /etc/sudoers, that lets you control commands like shutdown.

I think this is the wrong way to tackle the problem: sudo is for allowing users to execute commands they are normally not allowed to use. For instance: "shutdown" is only allowed for user "root", but you want to allow a specific user (other than root) to use this too (but not the other commands root is allowed to run). For this you create a sudo rule.

It doesn't make sense to control execution of each and every command in the system with sudo, because for this the normal filesystem flags (r-w-x) are sufficient. If you want all (normal) users not to use a specific command simply remove the x-flag from the executable and be done.

If you still need to use sudo at all after taking these considerations you could rewrite your code the following way:

Code:

echo -e "Press Control+C to finish"
#echo -e " "
while true ; do
     read whichcmd?"Enter Command: "
     if [ $(sudo -l | grep -c "$whichcmd") -gt 0 ] ; then
          sudo $whichcmd
     else
          $whichcmd
     fi
done

You will have to make sure in /etc/sudoers that "sudo -l" doesn't require a password, of course.

I hope this helps.

bakunin

bakunin is correct. Turning off/on each possible command is a waste of effort. Conversely, granting a blanket sudo to a user is promoting that user to a sysadmin, which is really a bad idea. For a variety of reasons.

sudo should be set up for a given user to do specific tasks.

We have "role" user accounts, that can only be accessed via su. These users are application owners, and can do maintenance, etc., on an app. That may be what you really want.

thanks guys

I know some commands are useless but I really don't want to complicate the end user and I need to have almost the same functionality as the normal shell

thanks a lot I' am going to try what you wrote here