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20231011110041-root.org

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+:PROPERTIES:
+:ID:       673d1cb1-536b-42f1-a046-40a8937c4283
+:END:
+#+title:  root
+#+filetags: :SYSTEM-INFORMATION:system:basics:
+
+Root user or otherwise also called super-user.  In computing, the superuser is a special user account used for system administration. Depending on the operating system (OS), the actual name of this account might be root, administrator, admin or supervisor. In some cases, the actual name of the account is not the determining factor; on Unix-like systems, for example, the user with a user identifier (UID) of zero is the superuser, regardless of the name of that account; and in systems which implement a role based security model, any user with the role of superuser (or its synonyms) can carry out all actions of the superuser account. The principle of least privilege recommends that most users and applications run under an ordinary account to perform their work, as a superuser account is capable of making unrestricted, potentially adverse, system-wide changes.
+
+* Unix
+In Unix-like computer OSes (such as [[id:5fada795-19a3-4ba6-97c0-0b70bd728a2f][Linux]]), root is the conventional name of the user who has all rights or permissions (to all files and programs) in all modes (single- or multi-user). Alternative names include baron in BeOS and avatar on some Unix variants. BSD often provides a toor ("root" written backward) account in addition to a root account. Regardless of the name, the superuser always has a user ID of 0. The root user can do many things an ordinary user cannot, such as changing the ownership of files and binding to network [[id:f4bb4857-2112-4e10-a22e-6da1436ce7b7][ports]] numbered below 1024.
+
+The name root may have originated because root is the only user account with permission to modify the root directory of a Unix system. This directory was originally considered to be root's home directory, but the UNIX Filesystem Hierarchy Standard now recommends that root's home be at /root. The first process bootstrapped in a Unix-like system, usually called init, runs with root privileges. It spawns all other processes directly or indirectly, which inherit their parents' privileges. Only a process running as root is allowed to change its user ID to that of another user; once it has done so, there is no way back. Doing so is sometimes called dropping root privileges and is often done as a security measure to limit the damage from possible contamination of the process. Another case is login and other programs that ask users for credentials and in case of successful authentication allow them to run programs with privileges of their accounts.
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+It is often recommended that root is never used as a normal user account, since simple typographical errors in entering commands can cause major damage to the system. Instead, a normal user account should be used, and then either the su (substitute user) or sudo (substitute user do) command is used. The su approach requires the user to know the root password, while the sudo method requires that the user be set up with the power to run "as root" within the /etc/sudoers file, typically indirectly by being made a member of the wheel,[8] adm, admin, or sudo group.
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+For a number of reasons, the sudo approach is now generally preferred – for example it leaves an audit trail of who has used the command and what administrative operations they performed.
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+Some OSes, such as macOS and some Linux distributions (most notably Ubuntu), automatically give the initial user created the ability to run as root via  [[id:dc54334e-afa9-4a53-be91-1e90bc6bf8d0][sudo]] – but this is configured to ask them for their password before doing administrative actions. In some cases the actual root account is disabled by default, so it can't be directly used. In mobile platform-oriented OSs such as Apple iOS and Android, superuser access is inaccessible by design, but generally the security system can be exploited in order to obtain it. In a few systems, such as Plan 9, there is no superuser at all.
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