File systemIn computing, a file system or filesystem (often abbreviated to fs) is a method and data structure that the operating system uses to control how data is stored and retrieved. Without a file system, data placed in a storage medium would be one large body of data with no way to tell where one piece of data stopped and the next began, or where any piece of data was located when it was time to retrieve it. By separating the data into pieces and giving each piece a name, the data are easily isolated and identified.
Cd (command)The command, also known as (change directory), is a command-line shell command used to change the current working directory in various operating systems. It can be used in shell scripts and s. The command has been implemented in operating systems such as Unix, DOS, IBM OS/2, MetaComCo TRIPOS, AmigaOS (where if a bare path is given, cd is implied), Microsoft Windows, ReactOS, and Linux. On MS-DOS, it is available in versions 2 and later. DR DOS 6.0 also includes an implementation of the and commands.
Directory (computing)In computing, a directory is a cataloging structure which contains references to other s, and possibly other directories. On many computers, directories are known as folders, or drawers, analogous to a workbench or the traditional office filing cabinet. The name derives from books like a telephone directory that lists the phone numbers of all the people living in a certain area. Files are organized by storing related files in the same directory.
Command-line interfaceA command-line interface (CLI) is a means of interacting with a device or computer program with commands from a user or client, and responses from the device or program, in the form of lines of text. Such access was first provided by computer terminals starting in the mid-1960s. This provided an interactive environment not available with punched cards or other input methods. Operating system command-line interfaces are often implemented with command-line interpreters or command-line processors.
Dir (command)In computing, dir (directory) is a command in various computer operating systems used for and directory listing. It is one of the basic commands to help navigate the . The command is usually implemented as an internal command in the command-line interpreter (shell). On some systems, a more graphical representation of the directory structure can be displayed using the tree command.
Command (computing)In computing, a command is a directive to a computer program to perform a specific task. It may be issued via a command-line interface, such as a shell, or as input to a network service as part of a network protocol, or as an event in a graphical user interface triggered by the user selecting an option in a menu. Specifically, the term command is used in imperative computer languages. The name arises because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages.
Environment variableAn environment variable is a user-definable value that can affect the way running processes will behave on a computer. Environment variables are part of the environment in which a process runs. For example, a running process can query the value of the TEMP environment variable to discover a suitable location to store s, or the HOME or USERPROFILE variable to find the directory structure owned by the user running the process.
Path (computing)A path is a string of characters used to uniquely identify a location in a directory structure. It is composed by following the directory tree hierarchy in which components, separated by a delimiting character, represent each directory. The delimiting character is most commonly the slash ("/"), the backslash character (""), or colon (":"), though some operating systems may use a different delimiter. Paths are used extensively in computer science to represent the directory/file relationships common in modern operating systems and are essential in the construction of Uniform Resource Locators (URLs).
Root directoryIn a computer , and primarily used in the Unix and Unix-like operating systems, the root directory is the first or top-most directory in a hierarchy. It can be likened to the trunk of a tree, as the starting point where all branches originate from. The root file system is the file system contained on the same disk partition on which the root directory is located; it is the filesystem on top of which all other file systems are mounted as the system boots up.
InodeThe inode (index node) is a data structure in a that describes a object such as a 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 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. There has been uncertainty on the Linux kernel mailing list about the reason for the "i" in "inode".
Multiuser DOSMultiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by Digital Research and acquired and further developed by Novell in 1991. Its ancestry lies in the earlier Digital Research 8-bit operating systems CP/M and MP/M, and the 16-bit single-tasking CP/M-86 which evolved from CP/M.
PATH (variable)PATH is an environment variable on Unix-like operating systems, DOS, OS/2, and Microsoft Windows, specifying a set of where executable programs are located. In general, each executing process or user session has its own PATH setting. Multics originated the idea of a search path. The early Unix shell only looked for program names in /bin, but by Version 3 Unix the directory was too large and /usr/bin, and a search path, became part of the operating system.
Home directoryA home directory is a on a multi-user operating system containing for a given user of the system. The specifics of the home directory (such as its name and location) are defined by the operating system involved; for example, Linux / BSD () systems use /home/ or /usr/home/ and Windows systems between 2000 and Server 2003 keep home directories in a folder named Documents and Settings. A user's home directory is intended to contain that user's files; including text documents, music, pictures, videos, etc.
MulticsMultics ("MULTiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory. Nathan Gregory writes that Multics "has influenced all modern operating systems since, from microcomputers to mainframes." Initial planning and development for Multics started in 1964, in Cambridge, Massachusetts. Originally it was a cooperative project led by MIT (Project MAC with Fernando Corbató) along with General Electric and Bell Labs.
File descriptorIn Unix and Unix-like computer operating systems, a file descriptor (FD, less frequently fildes) is a process-unique identifier (handle) for a or other input/output resource, such as a pipe or network socket. File descriptors typically have non-negative integer values, with negative values being reserved to indicate "no value" or error conditions. File descriptors are a part of the POSIX API.
