Root (computing)

Root can refer to the base of the file system's directory structure. See Root directory.

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In Unix style computer operating systems, root is the name of the user who has all rights on permissions in all modes (single or multi user). root is also called the superuser. Normally this is the administrator's account. The user root can do many things an ordinary user cannot, such as changing the ownership of files and binding to a server port. Generally, it is not good practice for anyone to use root as their normal user account, because simple typographic errors can cause major damage to the system. It is recommended to create a normal user account instead and then use the su command to switch when necessary.

Separation of administrative privileges from normal user privileges also makes an operating system more resistant to viruses and other malicious software, and the lack of this separation in DOS and earlier versions of Microsoft Windows has been cited as one major reason why these operating systems are more insecure.

Software defects which allow a user to gain root are a major security issue, and the fixing of such software is a major part of maintaining a secure system. One common way of gaining root is to cause a buffer overflow.

If a person 'has root access' it means that they are able to act as the administrator of that computer.

In the BeOS operating system, the superuser is named baron, while on some other Unix variants, it's named avatar. In Microsoft Windows NT and later systems derived from it (Windows 2000, Windows XP), the superuser is named Administrator.

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In a tree data type, the root is the node in the tree which has no parent node.