answer 1.
sudo is how you people higher privileges without root password.
Configuring sudo sudo is easy to configure and uses a straightforward syntax. You use the command visudo to edit the file /etc/sudoers. visudo is a wrapper around your favorite editor that does syntax checking on the file when you are finished editing it. By default, if you don’t have the EDITOR...
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answer 2.
You can use ssh-keygen to create ssh key pairs. This makes a private key and a public key.
You always keep the private key... ummm... private on your local computer.
normally every user has a .ssh directory in their home directory.
you can create a file called authorized_keys (it may already exist)
You can paste the public keys into this file.
This way, many people can login as the same user, but they will have different public keys
to identify who is actually logged in.
