Question: What is root and su?
Answer: On Linux and other Unix-like systems, root is the default username of the system administrator or super user (su). Typically, the root user is the only one that has complete read and write access on every file located on a server. Shared hosting accounts never allow root access, but if you are using a self-managed dedicated hosting service, you will probably need root access.
It is very unwise to login to your server directly as root. The more secure method is to login as a regular user with default permissions and then gain root access through the user. On Linux systems, you typically gain root access by typing “su” and then entering the password when prompted; however, some servers use sudo.
With sudo, you do not login directly as root. Instead, anytime you need to execute a root command, you put “sudo” in front of it. So, to remove a file, you would type “sudo rm filename”. It would then prompt you for the password. There has always been an ongoing to debate about which is more secure. With either method you need to be careful. Root has full access to your server. Use it wisely.