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Xargs
xargs (short for "extended arguments") is a command on Unix and most Unix-like operating systems used to build and execute commands from standard input. It converts input from standard input into arguments to a command. Some commands such as grep and awk can take input either as command-line arguments or from the standard input. However, others such as cp and echo can only take input as arguments, which is why xargs is necessary. A port of an older version of GNU is available for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities. A ground-up rewrite named is part of the open-source TextTools project. The command has also been ported to the IBM i operating system. Examples One use case of the xargs command is to remove a list of files using the rm command. POSIX systems have an for the maximum total length of the command line, so the command may fail with an error message of "Argument list too long" (meaning that t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-source Software
Open-source software (OSS) is Software, computer software that is released under a Open-source license, license in which the copyright holder grants users the rights to use, study, change, and Software distribution, distribute the software and its source code to anyone and for any purpose. Open-source software may be developed in a collaborative, public manner. Open-source software is a prominent example of open collaboration, meaning any capable user is able to online collaboration, participate online in development, making the number of possible contributors indefinite. The ability to examine the code facilitates public trust in the software. Open-source software development can bring in diverse perspectives beyond those of a single company. A 2024 estimate of the value of open-source software to firms is $8.8 trillion, as firms would need to spend 3.5 times the amount they currently do without the use of open source software. Open-source code can be used for studying and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porting
In software engineering, porting is the process of adapting software for the purpose of achieving some form of execution in a computing environment that is different from the one that a given program (meant for such execution) was originally designed for (e.g., different CPU, operating system, or third party library). The term is also used when software/hardware is changed to make them usable in different environments. Software is ''portable'' when the cost of porting it to a new platform is significantly less than the cost of writing it from scratch. The lower the cost of porting software relative to its implementation cost, the more portable it is said to be. This is distinct from cross-platform software, which is designed from the ground up without any single " native" platform. Etymology The term "port" is derived from the Latin '' portāre'', meaning "to carry". When code is not compatible with a particular operating system or architecture, the code must be "carried" to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sort (Unix)
In computing, sort is a standard command line program of Unix and Unix-like operating systems, that prints the lines of its input or concatenation of all files listed in its argument list in sorted order. Sorting is done based on one or more sort keys extracted from each line of input. By default, the entire input is taken as sort key. Blank space is the default field separator. The command supports a number of command-line options that can vary by implementation. For instance the "-r" flag will reverse the sort order. Sort ordering is affected by the environment's locale settings. History A command that invokes a general sort facility was first implemented within Multics. Later, it appeared in Version 1 Unix. This version was originally written by Ken Thompson at AT&T Bell Laboratories. By Version 4 Thompson had modified it to use pipes, but sort retained an option to name the output file because it was used to sort a file in place. In Version 5, Thompson invented "-" to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Locate (Unix)
locate is a Unix utility which serves to find files on filesystems. It searches through a prebuilt database of files generated by the updatedb command or by a daemon and compressed using incremental encoding. It operates significantly faster than find, but requires regular updating of the database. This sacrifices overall efficiency (because of the regular interrogation of filesystems even when no user needs information) and absolute accuracy (since the database does not update in real time) for significant speed improvements, particularly on very large filesystems. Implementations of locate locate was first created in 1982. The BSD and GNU Findutils versions derive from the original implementation. A locate command is also included in MacOS macOS, previously OS X and originally Mac OS X, is a Unix, Unix-based operating system developed and marketed by Apple Inc., Apple since 2001. It is the current operating system for Apple's Mac (computer), Mac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perl
Perl is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions. Perl originally was not capitalized and the name was changed to being capitalized by the time Perl 4 was released. The latest release is Perl 5, first released in 1994. From 2000 to October 2019 a sixth version of Perl was in development; the sixth version's name was changed to Raku. Both languages continue to be developed independently by different development teams which liberally borrow ideas from each other. Perl borrows features from other programming languages including C, sh, AWK, and sed. It provides text processing facilities without the arbitrary data-length limits of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Null Character
The null character is a control character with the value zero. Many character sets include a code point for a null character including Unicode (Universal Coded Character Set), ASCII (ISO/IEC 646), Baudot, ITA2 codes, the C0 control code, and EBCDIC. In modern character sets, the null character has a code point value of zero which is generally translated to a single code unit with a zero value. For instance, in UTF-8, it is a single, zero byte. However, in Modified UTF-8 the null character is encoded as two bytes : . This allows the byte with the value of zero, which is not used for any character, to be used as a string terminator. Originally, its meaning was like NOP when sent to a printer or a terminal, it had no effect (although some terminals incorrectly displayed it as space). When electromechanical teleprinters were used as computer output devices, one or more null characters were sent at the end of each printed line to allow time for the mechanism to return to the fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
POSIX Shell
A Unix shell is a command-line interpreter or shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts. Users typically interact with a Unix shell using a terminal emulator; however, direct operation via serial hardware connections or Secure Shell are common for server systems. All Unix shells provide filename wildcarding, piping, here documents, command substitution, variables and control structures for condition-testing and iteration. Concept Generally, a ''shell'' is a program that executes other programs in response to text commands. A sophisticated shell can also change the environment in which other programs execute by passing named variables, a parameter list, or an input source. In Unix-like operating systems, users typically have many choices of command-line interpret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallel (software)
GNU parallel is a command-line utility for Linux and other Unix-like operating systems which allows the user to execute shell scripts or commands in parallel. GNU parallel is free software, written by Ole Tange in Perl. It is available under the terms of GPLv3. Usage The most common usage is to replace the shell loop, for example while read x; do do_something "$x" done < list to the form of list contains arguments for do_something and where process_output may be empty.
Scripts using parallel are often easier to read than scripts using pexec.
The program parallel features also
* grouping of and < ...
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GNU Locate
GNU ( ) is an extensive collection of free software (394 packages ), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popularly known as Linux. Most of GNU is licensed under the GNU Project's own General Public License ( GPL). GNU is also the project within which the free software concept originated. Richard Stallman, the founder of the project, views GNU as a "technical means to a social end". Relatedly, Lawrence Lessig states in his introduction to the second edition of Stallman's book '' Free Software, Free Society'' that in it Stallman has written about "the social aspects of software and how Free Software can create community and social justice". Name ''GNU'' is a recursive acronym for "GNU's Not Unix!", chosen because GNU's design is Unix-like, but differs from Unix by being free software and containing no Unix code. Stallman chose the name by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Backtick
The backtick is a typographical mark used mainly in computing. It is also known as backquote, grave, or grave accent. The character was designed for typewriters to add a grave accent to a (lower-case) base letter, by overtyping it atop that letter. On early computer systems, however, this physical dead key+overtype function was rarely supported, being functionally replaced by precomposed characters. Consequently, this ASCII symbol was rarely (if ever) used in computer systems for its original aim and became repurposed for many unrelated uses in computer programming. The sign is located on the left-top of a US or UK layout keyboard, next to the key. Provision (if any) of the backtick on other keyboards varies by national keyboard layout and keyboard mapping. History Typewriters On typewriters designed for languages that routinely use diacritics (accent marks), there are two possible solutions. Keys can be dedicated to pre-composed characters or alternatively a dead key mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unix Shell
A Unix shell is a Command-line_interface#Command-line_interpreter, command-line interpreter or shell (computing), shell that provides a command line user interface for Unix-like operating systems. The shell is both an interactive command language and a scripting language, and is used by the operating system to control the execution of the system using shell scripts. Users typically interact with a Unix shell using a terminal emulator; however, direct operation via serial hardware connections or Secure Shell are common for server systems. All Unix shells provide filename Wildcard character, wildcarding, Pipeline (Unix), piping, here documents, command substitution, Variable (programming), variables and control flow, control structures for Conditional (programming), condition-testing and iteration. Concept Generally, a ''shell'' is a program that executes other programs in response to text commands. A sophisticated shell can also change the environment in which other programs exe ... [...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] |
