How to run a root/admin shell in Terminal? How can I run a shell as Admin in Terminal if Im logged in as User with standard privileges? I know the passwords for user and admin account
One easy way is to su to the admin user than use sudo -s to become root shell.

su - shortname_for_admin
sudo -s


This also is covered well in the linked questions:


Run sudo From Non-Admin Account
How do I run terminal in sudo mode?