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Variant Symlinks
In computing, a symbolic link (also symlink or soft link) is a file whose purpose is to point to a file or directory (called the "target") by specifying a path thereto. Symbolic links are supported by POSIX and by most Unix-like operating systems, such as FreeBSD, Linux, and macOS. Support also exists in Windows 10 and 11. CTSS on IBM 7090 had files linked by name in 1963. By 1978 minicomputer operating systems from DEC, and in Data General's RDOS included symbolic links. Overview A symbolic link contains a text string that is automatically interpreted and followed by the operating system as a path to another file or directory. This other file or directory is called the "target". The symbolic link is a second file that exists independently of its target. If a symbolic link is deleted, its target remains unaffected. If a symbolic link points to a target, and sometime later that target is moved, renamed or deleted, the symbolic link is not automatically updated or deleted, but ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology, and software engineering. The term ''computing'' is also synonymous with counting and calculation, calculating. In earlier times, it was used in reference to the action performed by Mechanical computer, mechanical computing machines, and before that, to Computer (occupation), human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tree (graph Theory)
In graph theory, a tree is an undirected graph in which any two vertices are connected by path, or equivalently a connected acyclic undirected graph. A forest is an undirected graph in which any two vertices are connected by path, or equivalently an acyclic undirected graph, or equivalently a disjoint union of trees. A directed tree, oriented tree,See .See . polytree,See . or singly connected networkSee . is a directed acyclic graph (DAG) whose underlying undirected graph is a tree. A polyforest (or directed forest or oriented forest) is a directed acyclic graph whose underlying undirected graph is a forest. The various kinds of data structures referred to as trees in computer science have underlying graphs that are trees in graph theory, although such data structures are generally rooted trees. A rooted tree may be directed, called a directed rooted tree, either making all its edges point away from the root—in which case it is called an arborescence or out-tree� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mv (Unix)
mv is a shell command for renaming and moving files and directories. If both items are on the same file system, the command renames; otherwise items are copied to the destination and the old items are removed (more specifically unlinked). To move between two directories, the user must have write permission for both because the command modifies the content of both. For a rename, an item's timestamp is not modified. On Unix implementations derived from AT&T Unix, cp, ln and mv are implemented as a single program with hard-linked binaries. History Multics provided a file move/rename command named . A version with the contracted name appeared in Version 1 Unix and became part of the X/Open Portability Guide issue 2 of 1987. The version in GNU Core Utilities was written by Mike Parker, David MacKenzie, and Jim Meyering. The command is available in Windows via UnxUtils. The command was ported to IBM i. Options Most implementations support: * -i interactive; the comma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rm (Unix)
rm, short for remove, is a shell command for removing files (which includes special files such as directories) from the file system. The command may not actually delete a file (release its storage for reuse) since it only unlinks it removes a hard link to a file via the unlink() system call. If a file has multiple links and less than all are removed, then the file remains in the file system; accessible via its other links. When a file's only link is removed, then the file is deleted releasing its storage space for other use. Generally, a deleted file's former storage space still contains the file's data until it is overwritten with another file's content. The data is not accessible via normal file operations but can be recovered via specialized tools. Since this is considered a security risk in some contexts, a hardened version of may wipe the file's storage area when the file is deleted. Commands such as shred and srm specifically provide data wiping. Since rm does no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unlink (Unix)
In Unix-like operating systems, unlink is a system call and a command line utility to delete files. The program directly interfaces the system call, which removes the file name and (but not on GNU systems) directories like rm and rmdir. If the file name was the last hard link to the file, the file itself is deleted as soon as no program has it open. Unlike the rm utility, the unlink utility only accepts one argument, which can be desirable to guard against accidental multi-deletions. It also appears in the PHP, Node.js, R, Perl and Python standard libraries in the form of the ''unlink()'' built-in function. Like the Unix utility, it is also used to delete files. Examples To delete a file named ''foo'', one could type: % unlink foo In PHP, one could use the following function to do the same: unlink("foo"); The Perl syntax is identical to the PHP syntax, save for the parentheses: unlink "foo"; In Node.js it is almost the same as the others: fs.unlink("foo", callb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Find (Unix)
In Unix-like operating systems, find is a command-line utility that locates files based on some user-specified criteria and either prints the pathname of each matched object or, if another action is requested, performs that action on each matched object. It initiates a search from a desired starting location and then recursively traverses the nodes (directories) of a hierarchical structure (typically a tree). find can traverse and search through different file systems of partitions belonging to one or more storage devices mounted under the starting directory. The possible search criteria include a pattern to match against the filename or a time range to match against the modification time or access time of the file. By default, find returns a list of all files below the current working directory, although users can limit the search to any desired maximum number of levels under the starting directory. The related locate programs use a database of indexed files obtained thro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Command-line Interface
A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternative to the non-interactive mode available with punched cards. For a long time, a CLI was the most common interface for software, but today a graphical user interface (GUI) is more common. Nonetheless, many programs such as operating system and software development utility software, utilities still provide CLI. A CLI enables automation, automating computer program, programs since commands can be stored in a scripting language, script computer file, file that can be used repeatedly. A script allows its contained commands to be executed as group; as a program; as a command. A CLI is made possible by command-line interpreters or command-line processors, which are programs that execute input commands. Alternatives to a CLI ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GitHub
GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug tracking system, bug tracking, software feature requests, task management, continuous integration, and wikis for every project. Headquartered in California, GitHub, Inc. has been a subsidiary of Microsoft since 2018. It is commonly used to host open source software development projects. GitHub reported having over 100 million developers and more than 420 million Repository (version control), repositories, including at least 28 million public repositories. It is the world's largest source code host Over five billion developer contributions were made to more than 500 million open source projects in 2024. About Founding The development of the GitHub platform began on October 19, 2005. The site was launched in April 2008 by Tom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Systems Research Group
The Computer Systems Research Group (CSRG) was a research group at the University of California, Berkeley, that was dedicated to enhancing AT&T Unix operating system and funded by the Defense Advanced Research Projects Agency. History Professor Bob Fabry of Berkeley acquired a UNIX source license from AT&T in 1974. His group started to modify UNIX, and distributed their version as the Berkeley Software Distribution (BSD). In April 1980, Fabry signed a contract with DARPA to develop UNIX even further and accommodate the specific requirements of the ARPAnet. With this funding, Fabry created the Computer Systems Research Group. By the early 1980s, CSRG was the best-known non-commercial Unix developer, and a majority of Unix sites used at least some Berkeley software. AT&T included some CSRG work in Unix System V. During the 1970s and 1980s, AT&T/USL raised the commercial licensing fee for UNIX from $20,000 to $100,000–$200,000. This became a big problem for small research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berkeley Software Distribution
The Berkeley Software Distribution (BSD), also known as Berkeley Unix or BSD Unix, is a discontinued Unix operating system developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berkeley, beginning in 1978. It began as an improved derivative of AT&T's original Unix that was developed at Bell Labs, based on the source code but over time diverging into its own code. BSD would become a pioneer in the advancement of Unix and computing. BSD's development was begun initially by Bill Joy, who added virtual memory capability to Unix running on a VAX-11 computer. In the 1980s, BSD was widely adopted by workstation vendors in the form of proprietary Unix distributions such as DEC Ultrix and Sun Microsystems SunOS due to its permissive licensing and familiarity to many technology company founders and engineers. It also became the most popular Unix at universities, where it was used for the study of operating systems. BSD was sponsored ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ln (Unix)
is a shell command for creating a link file to an existing file or directory. By default, the command creates a hard link, but with the command line option, it creates a symbolic link. Most systems disallow a hard link to a directory since such links could disrupt the structure of a file system and interfere with the operation of other utilities. The command can create a symbolic link to non-existent file. The command appeared in Issue 2 of the X/Open Portability Guidelines. The version in GNU Core Utilities was written by Mike Parker and David MacKenzie. The command is available in Windows via UnxUtils and has been ported to IBM i. Links A link allows more than one path to refer to the same file. A hard link is a directory entry that refers to a file's inode (an internal reference). A file can have multiple hard links each referring to the same inode. Creating a hard link does not copy the contents of the file; but merely causes another name to be associated with the sam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Directory Tree
In computing, a directory is a file system cataloging structure that contains references to other computer files, 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. In a hierarchical file system (that is, one in which files and directories are organized in a manner that resembles a tree), a directory contained inside another directory is called a subdirectory. The terms parent and child are often used to describe the relationship between a subdirectory and the directory in which it is cataloged, the latter being the parent. The top-most directory in such a filesystem, which does not have a parent of its own, is called the root directory. The freedesktop.org media type for dire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
