uniq(1) — Linux manual pages

Linux manual pages	Section 1: General Commands

DESCRIPTION

Filter adjacent matching lines from INPUT (or standard input), writing to OUTPUT (or standard output).

With no options, matching lines are merged to the first occurrence.

Mandatory arguments to long options are mandatory for short options too.

−c, −−count: prefix lines by the number of occurrences
−d, −−repeated: only print duplicate lines
−D, −−all−repeated[=delimit−method]: print all duplicate lines delimit−method={none(default),prepend,separate} Delimiting is done with blank lines
−f, −−skip−fields=N: avoid comparing the first N fields
−i, −−ignore−case: ignore differences in case when comparing
−s, −−skip−chars=N: avoid comparing the first N characters
−u, −−unique: only print unique lines
−z, −−zero−terminated: end lines with 0 byte, not newline
−w, −−check−chars=N: compare no more than N characters in lines
−−help: display this help and exit
−−version: output version information and exit

A field is a run of blanks (usually spaces and/or TABs), then non−blank characters. Fields are skipped before chars.

	Note
	'uniq' does not detect repeated lines unless they are adjacent. You may want to sort the input first, or use 'sort `−u`' without 'uniq'. Also, comparisons honor the rules specified by 'LC_COLLATE'.

Written by Richard M. Stallman and David MacKenzie.

Report uniq bugs to bug−coreutils@gnu.org

General help using GNU software: <http://www.gnu.org/gethelp/>