Linux User UID description

Linux User UID description-Linux general technology-Linux technology and application information, the following is a detailed description. UID: What is the user ID )?? Zookeeper Linux has several restrictions on UID:

Id range
User features of this ID

0
When the UID is 0, it indicates that this account is "System Administrator 』! So when you want to be another System Administrator account, you can change the UID of this account to 0. That is to say, the system administrator on a system does not have to be root! However, it is not recommended that the UID of multiple accounts be 0.

1 ~ 499
The ID reserved for the system. In fact, 1 ~ There are no different accounts between 65534, that is, there are no different UID except 0. It is just a habit to set a default account of less than 500 as a reserved account. The advantage is that, taking the startup service "named" of the famous DNS server as an example, the Default Account UID of all named in this program is 25, and when other accounts are 25, it may cause minor system problems! To prevent this problem, we recommend that you keep the UID before 500 to the system!

However, in general, 1 ~ 99 will be reserved for the default account of the system, and the remaining 100 ~ 499 is reserved for some services.

500 ~ 65535
For general users. In fact, the current linux core (2.6.x) can support UID numbers as large as 4294967295 (2 ^ 32-1.