Types of "Users" in Linux

There are different types of  accessibility options provided by Linux, from which one can choose respective access as per requirement. Linux provides 5 different alternatives to choose the accessibility.

They are as listed below.

Super User or Root User (Like Administrator in Windows) : A special kind of user account which holds all kind’s of permissions to do any alteration to a programs or services of Linux. Especially this kind of  user account is used for  system administration. He can control and limit the access of other User’s. As  all the powers is vested for Root User, care has to be taken before performing each and every modifications, if anything goes wrong, no option left other than crash of  Kernel. It is very sensitive with unlimited accessibility. Take care before performing any step in root.

 System User: It is created by default by the OS. This type of user is similar to normal user but got more privileges and access to secure programs which normal user doesn’t got authentication.

Normal User : These are the users which have been created by the Root and has limited access to the resources and need permission from Root to access any secure resources and services.

Network User (Remote User) : A user that can remotely access the linux machine from a different location. 

Pseudo User: It’s a replica of Root User, is used when a user needs the permissions similar to  Root User. Only  Root User can give the access to this user account for others.

Every Users got their own identity and authenticity. When we say Identity of the User,UID (User identifier) comes into picture.  UID  is a unique identity, simply a number given to the user.

Every kind of User type as discussed above are given a particular range of UID’s.

Root User got the UID ‘0‘ . {As root user is prime and supreme authoritative, so he got the UID ” 0 “, This can be altered in the configuration file, which we come across later}

UID for System User lies with in the range of 1 to 499. {Don’t come to a conclusion that Linux OS can only provide 500 System Users. It’s just a default range provided by the OS, it can be altered and can add system users greater than 500 but less than a saturation value which depends on a type Linux OS}

UID for Normal User lies with in the range of > 500 <6000.

UID for Network User lies with in the range of  >6000.

To check which type of user are you logged in, simply do the following.

[root@localhost~]# whoami

root