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Linux Commands
This is a list of POSIX (Portable Operating System Interface) commands as specified by IEEE Std 1003.1-2008, which is part of the Single UNIX Specification (SUS). These commands can be found on Unix operating systems and most Unix-like operating systems. This is not a comprehensive list of all utilities that existed in the various historic Unix and Unix-like systems, as it excludes utilities that were not mandated by the aforementioned standard. List See also * List of GNU Core Utilities commands * GNOME Core Applications * List of GNU packages * List of KDE applications * List of Unix daemons * List of web browsers for Unix and Unix-like operating systems * Unix philosophy The Unix philosophy, originated by Ken Thompson, is a set of cultural norms and philosophical approaches to minimalist, modular software development. It is based on the experience of leading developers of the Unix operating system. Early Unix d ... * Footnotes External links IEEE Std 1003.1,20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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POSIX Utilities
The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming interfaces (APIs), along with command line shells and utility interfaces, for software compatibility (portability) with variants of Unix and other operating systems. POSIX is also a trademark of the IEEE. POSIX is intended to be used by both application and system developers. Name Originally, the name "POSIX" referred to IEEE Std 1003.1-1988, released in 1988. The family of POSIX standards is formally designated as IEEE 1003 and the ISO/IEC standard number is ISO/ IEC 9945. The standards emerged from a project that began in 1984 building on work from related activity in the ''/usr/group'' association. Richard Stallman suggested the name ''POSIX'' (pronounced as ''pahz-icks,'' as in ''positive'', not as ''poh-six'') to the IEEE instead of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Arbitrary-precision Arithmetic
In computer science, arbitrary-precision arithmetic, also called bignum arithmetic, multiple-precision arithmetic, or sometimes infinite-precision arithmetic, indicates that calculations are performed on numbers whose digits of precision are limited only by the available memory of the host system. This contrasts with the faster fixed-precision arithmetic found in most arithmetic logic unit (ALU) hardware, which typically offers between 8 and 64 bits of precision. Several modern programming languages have built-in support for bignums, and others have libraries available for arbitrary-precision integer and floating-point math. Rather than storing values as a fixed number of bits related to the size of the processor register, these implementations typically use variable-length arrays of digits. Arbitrary precision is used in applications where the speed of arithmetic is not a limiting factor, or where precise results with very large numbers are required. It should not b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cksum
cksum is a command in Unix and Unix-like operating systems that generates a checksum value for a file or stream of data. The cksum command reads each file given in its arguments, or standard input if no arguments are provided, and outputs the file's 32-bit cyclic redundancy check (CRC) checksum and byte count. The CRC output by cksum is different from the CRC-32 used in zip, PNG and zlib. The cksum command can be used to verify that files transferred by unreliable means arrived intact. However, the CRC checksum calculated by the cksum command is not cryptographically secure: While it guards against ''accidental'' corruption (it is unlikely that the corrupted data will have the same checksum as the intended data), it is not difficult for an attacker to ''deliberately'' corrupt the file in a specific way that its checksum is unchanged. Unix-like systems typically include other commands for cryptographically secure checksums, such as sha256sum. The command is available as a sepa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Chown
The command , an abbreviation of ''change owner'', is used on Unix and Unix-like operating systems to change the owner of file system files, directories Directory may refer to: * Directory (computing), or folder, a file system structure in which to store computer files * Directory (OpenVMS command) * Directory service, a software application for organizing information about a computer network's .... Unprivileged (regular) users who wish to change the group membership of a file that they own may use . The ownership of any file in the system may only be altered by a super-user. A user cannot ''give away'' ownership of a file, even when the user owns it. Similarly, only a member of a group can change a file's ''group ID'' to that group. The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. The command has also been ported to the IBM i operating system. See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Chmod
In Unix and Unix-like operating systems, is the command and system call used to change the access permissions and the special mode flags (the ''setuid'', ''setgid'', and ''sticky'' flags) of file system objects ( files and directories). Collectively these were originally called its modes, and the name was chosen as an abbreviation of ''change mode''. History A command first appeared in AT&T UNIX version 1, along with the system call. As systems grew in number and types of users, access-control lists were added to many file systems in addition to these most basic modes to increase flexibility. The version of bundled in GNU coreutils was written by David MacKenzie and Jim Meyering. The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. The command has also been ported to the IBM i operating system. Command syntax Throughout this section, ''ser'' refers to the ow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Chgrp
The (from change group) command may be used by unprivileged users on various operating systems to change the group associated with a file system object (such as a computer file, directory, or link) to one of which they are a member. A file system object has 3 sets of access permissions, one set for the owner, one set for the group and one set for others. Changing the group of an object could be used to change which users can write to a file. History The command was originally developed as part of the Unix operating system by AT&T Bell Laboratories. It is also available in the Plan 9 and Inferno operating systems and in most Unix-like systems. The command has also been ported to the IBM i operating system. Syntax chgrp 'options''''group'' ''FSO'' * The ''group'' parameter specifies the new group with which the files or directories should be associated. It may either be a symbolic name or an identifier. * The ''FSO'' specifies one or more file system objects, which ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Call Graph
A call graph (also known as a call multigraph) is a control-flow graph, which represents calling relationships between subroutines in a computer program. Each node represents a procedure and each edge ''(f, g)'' indicates that procedure ''f'' calls procedure ''g''. Thus, a cycle in the graph indicates recursive procedure calls. Basic concepts Call graphs can be dynamic or static. A dynamic call graph is a record of an execution of the program, for example as output by a profiler. Thus, a dynamic call graph can be exact, but only describes one run of the program. A static call graph is a call graph intended to represent every possible run of the program. The exact static call graph is an undecidable problem, so static call graph algorithms are generally overapproximations. That is, every call relationship that occurs is represented in the graph, and possibly also some call relationships that would never occur in actual runs of the program. Call graphs can be defined to represent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cflow
GNU cflow is a flow graph generator that is part of the GNU Project. It reads a collection of C source files and generates a C flow graph of external references. It uses only sources and doesn't need to run the program. History It was initially an implementation of the UNIX Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ... utility cflow. cflow (UNIX utility) cflow is a Unix command generating a C-language flowgraph. Besides GNU, there are other implementations of ''cflow'', like the one for Tru64 Unix.« cflow - Tru64 Unix » ''HP website'', 2011. References < ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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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 batch files. Implementations 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. The command is also available in the open source MS-DOS emulator DOSBox and in the EFI shell. It is named in HP MPE/iX. The command is analogous to the Stratus OpenVOS command. is frequently included built directly into a command-line interpreter. This is the case in most of the Unix shells ( Bourne shell, tcsh, bash, etc.), cmd.exe on Microsoft Windows NT/2000+ and Windows PowerShell on Windows 7+ and COMMAND.COM on DOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cat (Unix)
cat is a standard Unix utility that reads files sequentially, writing them to standard output. The name is derived from its function to (con)catenate files (from Latin ''catenare'', "to chain"). It has been ported to a number of operating systems. History cat was part of the early versions of Unix, e.g., Version 1, and replaced pr, a PDP-7 and Multics utility for copying a single file to the screen. It was written by Ken Thompson and Dennis Ritchie. The version of cat bundled in GNU coreutils was written by Torbjorn Granlund and Richard Stallman. The ReactOS version was written by David Welch, Semyon Novikov, and Hermès Bélusca. Over time, alternative utilities such as tac and bat also became available, bringing different new features. Usage The Single Unix Specification defines the operation of cat to read files in the sequence given in its arguments, writing their contents to the standard output in the same sequence. The specification mandates the support of one o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cal (command)
is a command-line utility on a number of computer operating systems including Unix, Plan 9, Inferno and Unix-like operating systems such as Linux that prints an ASCII calendar of the given month or year. If the user does not specify any command-line options, cal will print a calendar of the current month. The command is a standard program on Unix and specified in the Single UNIX Specification. Implementations The cal command was present in 1st Edition Unix. A cal command is also part of ASCII's ''MSX-DOS2 Tools'' for MSX-DOS version 2. It is also available for FreeDOS. This implementation only supports the Gregorian calendar (New Style) and may be distributed freely, with or without source. The FreeDOS version was developed by Charles Dye. Examples $ cal March 1984 Su Mo Tu We Th Fr Sa 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 $ cal -3 (shows the previous, current and next month) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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C (programming Language)
C (''pronounced like the letter c'') is a General-purpose language, general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities of the targeted CPUs. It has found lasting use in operating systems, device drivers, protocol stacks, though decreasingly for application software. C is commonly used on computer architectures that range from the largest supercomputers to the smallest microcontrollers and embedded systems. A successor to the programming language B (programming language), B, C was originally developed at Bell Labs by Ritchie between 1972 and 1973 to construct utilities running on Unix. It was applied to re-implementing the kernel of the Unix operating system. During the 1980s, C gradually gained popularity. It has become one of the measuring programming language popularity, most widely used programming languages, with C compilers avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |