Search results
Results from the WOW.Com Content Network
The original Unix file system supported three types of files: ordinary files, directories, and "special files", also termed device files. [1] The Berkeley Software Distribution (BSD) and System V each added a file type to be used for interprocess communication: BSD added sockets, [3] while System V added FIFO files.
A reference to a location in a directory system is called a path. In many operating systems, programs have an associated working directory in which they execute. Typically, file names accessed by the program are assumed to reside within this directory if the file names are not specified with an explicit directory name.
Unix abstracts the nature of this tree hierarchy entirely and in Unix and Unix-like systems the root directory is denoted by the / (slash) sign. Though the root directory is conventionally referred to as /, the directory entry itself has no name – its path is the "empty" part before the initial directory separator character (/).
This was an artifact of early Unix programming. Specifically, when Ken Thompson and Dennis Ritchie were migrating Unix to a PDP-11, the contents of the /bin and /lib directories, which were to be the first directories mounted on startup and to contain all essentials for the OS to function, became too large to fit on an RK05 disk drive. So they ...
The most common special file is the directory. The layout of a directory file is defined by the filesystem used. As several filesystems are available under Unix, both native and non-native, there is no one directory file layout. A directory is marked with a d as the first letter in the mode field in the output of ls -dl [5] or stat, e.g.
By contrast, Unix uses the hyphen-minus character ("-") as a command-line switch prefix. When directory support was added to MS-DOS in version 2.0, "/" was kept as the switch prefix character for backward compatibility. Microsoft chose the backslash character ("\") as a directory separator, which looks similar to the slash character, though ...
Unix popularized a syntax for regular expressions that found widespread use. The Unix programming interface became the basis for a widely implemented operating system interface standard (POSIX, see above). The C programming language soon spread beyond Unix, and is now ubiquitous in systems and applications programming.
Version 1 AT&T UNIX printf: Shell programming Mandatory Write formatted output 4.3BSD-Reno prs: SCCS Optional (XSI) Print an SCCS file PWB UNIX ps: Process management Mandatory Report process status Version 4 AT&T UNIX pwd: Filesystem Mandatory Print working directory Version 5 AT&T UNIX read: Shell programming Mandatory Read a line from ...