Cannabaceae

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This article is about the command-line utility. For other uses, see Uniq (disambiguation).
uniq
Original author(s)Ken Thompson
(AT&T Bell Laboratories)
Developer(s)Various open-source and commercial developers
Initial releaseFebruary 1973; 51 years ago (1973-02)
Written inC
Operating systemUnix, Unix-like, Plan 9, Inferno, MSX-DOS, IBM i
PlatformCross-platform
TypeCommand
Licensecoreutils: GPLv3+
Plan 9: MIT License
Websiteman7.org/linux/man-pages/man1/uniq.1.html

uniq is a utility command on Unix, Plan 9, Inferno, and Unix-like operating systems which, when fed a text file or standard input, outputs the text with adjacent identical lines collapsed to one, unique line of text.

Overview[edit]

The command is a kind of filter program. Typically it is used after sort. It can also output only the duplicate lines (with the -d option), or add the number of occurrences of each line (with the -c option). For example, the following command lists the unique lines in a file, sorted by the number of times each occurs: 

$ sort file | uniq -c | sort -n

Using uniq like this is common when building pipelines in shell scripts.

History[edit]

First appearing in Version 3 Unix,[1] uniq is now available for a number of different Unix and Unix-like operating systems. It is part of the X/Open Portability Guide since issue 2 of 1987. It was inherited into the first version of POSIX and the Single Unix Specification.[2]

The version bundled in GNU coreutils was written by Richard Stallman and David MacKenzie.[3]

A uniq command is also part of ASCII's MSX-DOS2 Tools for MSX-DOS version 2.[4]

The command is available as a separate package for Microsoft Windows as part of the GnuWin32 project[5] and the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.[6]

The uniq command has also been ported to the IBM i operating system.[7]

See also[edit]

References[edit]

  1. ^ McIlroy, M. D. (1987). A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 (PDF) (Technical report). CSTR. Bell Labs. 139.
  2. ^ uniq – Shell and Utilities Reference, The Single UNIX Specification, Version 4 from The Open Group
  3. ^ uniq(1) – Linux General Commands Manual
  4. ^ MSX-DOS2 Tools User's Manual by ASCII Corporation
  5. ^ CoreUtils for Windows
  6. ^ Native Win32 ports of some GNU utilities
  7. ^ IBM. "IBM System i Version 7.2 Programming Qshell" (PDF). IBM. Retrieved 2020-09-05.

External links[edit]

source: https://en.wikipedia.org/wiki/Uniq

One thought on “Cannabaceae”

  1. Well, that’s interesting to know that Psilotum nudum are known as whisk ferns. Psilotum nudum is the commoner species of the two. While the P. flaccidum is a rare species and is found in the tropical islands. Both the species are usually epiphytic in habit and grow upon tree ferns. These species may also be terrestrial and grow in humus or in the crevices of the rocks.
    View the detailed Guide of Psilotum nudum: Detailed Study Of Psilotum Nudum (Whisk Fern), Classification, Anatomy, Reproduction

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