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Group Identifier
In Unix-like systems, multiple users can be put into '' groups''. POSIX and conventional Unix file system permissions are organized into three classes, ''user'', ''group'', and ''others''. The use of groups allows additional abilities to be delegated in an organized fashion, such as access to disks, printers, and other peripherals. This method, among others, also enables the superuser to delegate some administrative tasks to normal users, similar to the ''Administrators'' group on Microsoft Windows NT and its derivatives. A group identifier, often abbreviated to GID, is a numeric value used to represent a specific group. The range of values for a GID varies amongst different systems; at the very least, a GID can be between 0 and 32,767, with one restriction: the login group for the superuser must have GID 0. This numeric value is used to refer to groups in the /etc/passwd and /etc/group files or their equivalents. Shadow password files and Network Information Service also re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix-like
A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Unix-like Application software, application is one that behaves like the corresponding List of POSIX commands, Unix command or Unix shell, shell. Although there are general Unix philosophy, philosophies for Unix design, there is no technical standard defining the term, and opinions can differ about the degree to which a particular operating system or application is Unix-like. Some well-known examples of Unix-like operating systems include Linux, FreeBSD and OpenBSD. These systems are often used on servers as well as on personal computers and other devices. Many popular applications, such as the Apache HTTP Server, Apache web server and the Bash (Unix shell), Bash shell, are also designed to be used on Unix-like systems. Definition The Open ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Effective User ID
Effectiveness or effectivity is the capability of producing a desired result or the ability to produce desired output. When something is deemed effective, it means it has an intended or expected outcome, or produces a deep, vivid impression. Etymology The origin of the word ''effective'' stems from the Latin word , which means "creative, productive, or effective". It surfaced in Middle English between 1300 and 1400 AD. Usage Science and technology Mathematics and logic In mathematics and logic, ''effective'' is used to describe metalogical methods that fit the criteria of an effective procedure. In group theory, a group element acts ''effectively'' (or ''faithfully'') on a point, if that point is not fixed by the action. Physics In physics, an effective theory is, similar to a phenomenological theory, a framework intended to explain certain (observed) effects without the claim that the theory correctly models the underlying (unobserved) processes. In heat t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FAT Access Rights
In nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such compounds, most commonly those that occur in living beings or in food. The term often refers specifically to triglycerides (triple esters of glycerol), that are the main components of vegetable oils and of fatty tissue in animals; or, even more narrowly, to triglycerides that are solid or semisolid at room temperature, thus excluding oils. The term may also be used more broadly as a synonym of lipid—any substance of biological relevance, composed of carbon, hydrogen, or oxygen, that is insoluble in water but soluble in non-polar solvents. In this sense, besides the triglycerides, the term would include several other types of compounds like mono- and diglycerides, phospholipids (such as lecithin), sterols (such as cholesterol), waxes (such as beeswax), and free fatty acids, which are usually present in human diet in smaller amounts. Fats are one of the three main ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inode
An inode (index node) is a data structure in a Unix-style file system that describes a file-system object such as a file or a directory. Each inode stores the attributes and disk block locations of the object's data. File-system object attributes may include metadata (times of last change, access, modification), as well as owner and permission data. A directory is a list of inodes with their assigned names. The list includes an entry for itself, its parent, and each of its children. Etymology There has been uncertainty on the Linux kernel mailing list about the reason for the "i" in "inode". In 2002, the question was brought to Unix pioneer Dennis Ritchie, who replied: A 1978 paper by Ritchie and Ken Thompson bolsters the notion of "index" being the etymological origin of inodes. They wrote: Additionally, Maurice J. Bach wrote that the word ''inode'' "is a contraction of the term index node and is commonly used in literature on the UNIX system". Details A file system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Process Identifier
In computing, the process identifier (a.k.a. process ID or PID) is a number used by most operating system kernel (operating system), kernels—such as those of Unix, macOS and Windows—to uniquely identify an active Process (computing), process. This number may be used as a parameter in various function calls, allowing processes to be manipulated, such as adjusting the process's priority or kill (command), killing it altogether. Unix-like In Unix-like operating systems, new processes are created by the Fork (operating system), fork() system call. The PID is returned to the parent process, enabling it to refer to the child in further function calls. The parent may, for example, wait for the child to terminate with the waitpid() function, or terminate the process with kill(). There are two tasks with specially distinguished process IDs: PID 0 is used for ''swapper'' or ''sched'', which is part of the kernel and is a process that runs on a CPU core whenever that CPU core has not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
User Identifier
Unix-like operating systems identify a user by a value called a user identifier, often abbreviated to user ID or UID. The UID, along with the group identifier (GID) and other access control criteria, is used to determine which system resources a user can access. The Passwd (file), password file maps textual user names to UIDs. UIDs are stored in the inodes of the Unix file system, running processes, tar archives, and the now-obsolete Network Information Service. In POSIX-compliant environments, the shell command id gives the current user's UID, as well as more information such as the user name, primary user group and group identifier (GID). Process attributes The POSIX standard introduced three different UID fields into the process descriptor table, to allow privileged processes to take on different roles dynamically: Effective user ID The effective UID (euid) of a process is used for most access checks. It is also used as the owner for files created by that process. The effectiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umask
umask is a shell command that reports or sets the mask value that limits the file permissions for newly created files in many Unix and Unix-like file systems. A system call with the same name, , provides access to the mask value stored in the operating system (OS), and the command provides shell user access to the system call. Additionally, the mask value, formally ''file mode creation mask'', is often referred to as the ''umask''. When a new file is created, its access permissions are restricted by the stored umask mask value. The file's permission bits that each grant access are cleared by corresponding bits of the mask that are set. Set bits of the mask disallow the permission and clear bits of the mask allow the permission. The otherwise default value of a file's permissions is defined elsewhere. The mask just prevents corresponding bits of the default. The mask acts as a last-stage filter that strips away permissions as a file is created; each bit that is set strips away ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NFSv4
Network File System (NFS) is a distributed file system protocol originally developed by Sun Microsystems (Sun) in 1984, allowing a user on a client computer to access files over a computer network much like local storage is accessed. NFS, like many other protocols, builds on the Open Network Computing Remote Procedure Call (ONC RPC) system. NFS is an open IETF standard defined in a Request for Comments (RFC), allowing anyone to implement the protocol. Versions and variations Sun used version 1 only for in-house experimental purposes. When the development team added substantial changes to NFS version 1 and released it outside of Sun, they decided to release the new version as v2, so that version interoperation and RPC version fallback could be tested. NFSv2 Version 2 of the protocol (defined in , March 1989) originally operated only over User Datagram Protocol (UDP). Its designers meant to keep the server side stateless, with locking (for example) implement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Setgid
The Unix and Linux access rights flags setuid and setgid (short for ''set user identity'' and ''set group identity'') allow users to run an executable with the file system permissions of the executable's owner or group respectively and to change behaviour in directories. They are often used to allow users on a computer system to run programs with temporarily elevated privileges to perform a specific task. While the assumed user id or group id privileges provided are not always elevated, at a minimum they are specific. The flags setuid and setgid are needed for tasks that require different privileges than what the user is normally granted, such as the ability to alter system files or databases to change their login password. Some of the tasks that require additional privileges may not immediately be obvious, though, such as the ping command, which must send and listen for control packets on a network interface. File modes The setuid and setgid bits are normally represented as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Setuid
The Unix and Linux access rights flags setuid and setgid (short for ''set user identity'' and ''set group identity'') allow users to run an executable with the file system permissions of the executable's owner or group respectively and to change behaviour in directories. They are often used to allow users on a computer system to run programs with temporarily elevated privileges to perform a specific task. While the assumed user id or group id privileges provided are not always elevated, at a minimum they are specific. The flags setuid and setgid are needed for tasks that require different privileges than what the user is normally granted, such as the ability to alter system files or databases to change their login password. Some of the tasks that require additional privileges may not immediately be obvious, though, such as the ping command, which must send and listen for control packets on a network interface. File modes The setuid and setgid bits are normally represented a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saved User ID
Save, SAVE, or Saved may refer to: Places *Save (Garonne), a river in southern France *Save River (Africa), a river in Zimbabwe and Mozambique *Sava, a river in Eastern Europe also known as Save * Savè, Benin, a commune and city * Save, Rwanda, a settlement * Säve, a locality in Göteborg Municipality, Västra Götaland County, Sweden ** Säve Airport * Esquel Airport (ICAO airport code: SAVE; IATA airport code: EQS), Esquel, Chubut Province, Argentina Organizations, groups, companies *Spirit Airlines (NASDAQ stockticker: SAVE), a U.S. airline Charities * Society Against Violence in Education, a non-profit organization working against ragging in India * Save Britain's Heritage (''SAVE''), a historic building conservation group in the United Kingdom In technology *Saved game, saved progress of a player in a video game *Computer files are "saved" to achieve persistence In media and entertainment Music * ''Saved'' (Bob Dylan album), 1980, or the song * ''Saved'' (Now, Now albu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
