Macos – How to execute a command with admin privileges and access to files of the logged in user

macosprivilegessudo

I have some problems understanding sudo. I am logged in on a terminal as an non-admin/non-root user. This "normal" user is not in the sudoers file (and shouldnt be, in my opinion).

Now I try to execute a command that needs admin/root privileges and also access to directories of my normal user – therefore I am not able
to simply su into an admin or root user.

In my understanding sudo -u root should do the trick – however
it doesn't accept the password for root (or admin if I try with my normal
admin user). It only accepts the password of the "normal" user which seems
to indicate that the -u username option doesn't work the way I expect it to
work.

My expectation is that sudo -u root some_command executes some_command
with the privileges of root and therefore it asks also for the password of root.
Obviously not.

TL;DR: How do I execute any command that requires admin
privileges AND has access to the files of the "logged in (normal) user" without
adding the normal user to the sudoers file?

I have enabled the root user under Mac OS X 10.7.

Best Answer

sudo always requires the executing user's password (and requires that you have specific permissions to do this, i.e. are one of the sudoers).

su requires the password of the target account (root by default, but root account has no password on OS X by default). If you use su instead, you can enter the destination account's password and execute a command using that user's privileges.

su -c some_cmd # as root
su username -c some_cmd # as username

This works by passing all arguments after the user name to the destination account's login shell. Shells usually support -c <commands> arguments. In GNU coreutils su, there's an actual -c command argument to su that can be placed before the user name.

You can su to another user account (using the other user account's password), and sudo from there, provided that other account is a sudoer.

If you want neither to enter another account's password, nor give your regular account sudoers permissions, you're pretty much out of options unless you consider SSH with key authentication or something like that.

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