What is the super user
In all Linux systems, the systems are distinguished by UID user privilege levels, and the user with UID 0 are to be agreed upon system has super powers. Super User has agreed to operate within the system the highest authority beauties, so that users can complete all the tools super system management; we can look up the user with UID 0 through the / etc / passwd is the root, and only root corresponding UID 0, from this point of view, root user is irreplaceable supremacy and unrestricted privileges in the system. In the system, the root user is a super user;
Appreciated UID corresponding relationship between the user and
When the system is installed by default, and users of the system UID is one to one relationship, that is to say a UID of a user. We know that the user identity is confirmed by UID, we are "user (user) and user groups (group) Profile explain" Commentary UID in there talking about "UID is to confirm that identifies the user permissions, user login system role at is achieved by UID, rather than a user name; the number of users sharing a UID is dangerous, such as our regular user's UID to 0, and share a root UID, which in fact has caused the system confusion administrative rights if we want to, can be achieved by using sudo or su root privileges;. must not be arbitrary and let a user to share a root with UID; "
In the system, can not let the UID and user-many relationship? We can, for example, we can put a UID assigned to several users to share this value is 0, which is the relationship between the UID and user-to-many. But this was a little dangerous; UID the same user with the same status and privileges. For example, we put in the system beinan the ordinary user's UID changed to 0, the fact that the average user will have the super powers, his ability and authority and as the root user; user beinan all operations will be identified as the root of operation because beinan UID of 0, 0 and UID for the user is root, is not it a bit disturbing mouth? Can be understood as user with UID 0 is the root, root user's UID is 0;
When one correspondence between UID and users, just ask the administrator for system management, to adhere to the guidelines, because the system security is the first one. So we put the Super privilege reserved for the root user only this is the best choice;
If we do not share the values of the UID 0 to other users, only the root user is the sole owner UID = 0, then, the root user is the only super user privileges;
Ordinary users and user masquerading
The super user is relatively ordinary users and virtual (also known as masquerading user), and camouflage ordinary users are restricted users; but in order to accomplish a specific task, ordinary users and user masquerading also necessary; Linux is a multi-user , multi-tasking operating systems, multi-user role is mainly reflected in the diversity of users, assign permissions to different users are different; more secure than Windows systems the essence of which is the Linux system, even now the latest version of Windows 2003, can not erase the stigma of its single-user system;