12.6 User Change
After the user account is created on the system, there may be a case where the contents of various items defined for the user account need to be changed.
12.6.1 “usermod” Command – Change User
You can use the “usermod” command to change all defined contents of a user account.
12.5 “deluser” Command – Delete User
You need to delete user account that is not needed on your system.
When deleting a user account, you can use “deluser” and “userdel” commands. The “deluser” command makes it easy to create user account. On the other hand, the “userdel” command can handle relatively detailed processing with very low-level commands, but it is complex to use and is not well used for general purposes.
12.4.3 “adduser” Command – Create User
You can use “adduser” and “useradd” commands to create user accounts. The “adduser” command makes it easy to create user accounts. The “useradd” command can handle relatively detailed processing with very low-level commands, but it is complex to use and generally not used for general purposes.
12.4.2 Necessary Considerations for Creating User
There are several things to consider when creating a new user account. When creating a user account, the basic management items to be checked are as follows:
■ Items about passwords
■ Items about user groups
12.4 Creating User
12.4.1 Necessity for Creating User
The Raspberry Pi system provides user accounts “pi” and “root” by default, but these user accounts are defined to be used by system administrators or system operators for system management purposes. They are are not suitable for use of normal user other than system administrators or system operators. There may be also several system administrators and system operators, not just one person, and there are cases in which responsibility and authority are separated according to their respective duties. Therefore, a newly created user is necessary for these users to access the Raspberry Pi system. These user accounts are created by system administrators with super user privileges, and are created by restricting the operations or privileges that can be used to suit the tasks of users who use the user accounts.
12.3 Managing User Account in the System
In the Raspberry Pi system, user groups are maintained in “/etc/passwd” file. Internally managed data has the following format.
: x:: :::
12.2.2 Working user
12.2.2.1 Meaning or Working user
The working user is the User ID used for the current work. Typically, the logon user is the working user, but in some cases you can use a different user ID to process the work. For example, if the logon user is “pi”, you can use the “root” user account instead of the “pi” user account to perform the tasks that require the root account.
12.2 Logon User and Working user
12.2.1 Logon User
12.2.1.1 Meaning of Logon User
The logon user literally means the user ID that was used to logon after booting the system, which is not changed until the system is booted again.
12.1.3 Super User and Normal User
12.1.3.1 Super User
A super user is a user who is authorized to do all the work on the system. This user can access all the data on the system, run all the programs, modify the behavior and contents of the system, and even have the right to destroy the system.
The Raspberry Pi system provides a super user account named “root” by default when the system is installed at first. Basically, it has the following features:
12.1.2 System Administrator and Normal User
12.1.2.1 System Administrator
A system administrator is a user account that is used to install a system or to manage critical tasks or privileges on the system. In the Raspberry Pi system, “pi” and “root” are provided for system management. If you want to use other user accounts besides the default user accounts, you need to create a new account.