|Original author(s)||Ken Thompson|
(AT&T Bell Laboratories)
|Developer(s)||Various open-source and commercial developers|
|Initial release||February 1973|
|Operating system||Unix, Unix-like, Plan 9, Inferno, MSX-DOS, IBM i|
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.
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
First appearing in Version 3 Unix,
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.
- McIlroy, M. D. (1987). A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 (PDF) (Technical report). CSTR. Bell Labs. 139.
- The Single UNIX Specification, Issue 7 from The Open Group – Commands & Utilities Reference,
- Linux General Commands Manual –
- MSX-DOS2 Tools User's Manual by ASCII Corporation
- CoreUtils for Windows
- Native Win32 ports of some GNU utilities
- IBM. "IBM System i Version 7.2 Programming Qshell" (PDF). Retrieved 2020-09-05.
|The Wikibook Guide to Unix has a page on the topic of: Commands|