## NAME

uniq - report or omit repeated lines

## SYNOPSIS

uniq [OPTION]... [INPUT [OUTPUT]]

## 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, one for each group

-D, --all-repeated[=METHOD] print all duplicate lines groups can be delimited with an empty line METHOD={none(default),prepend,separate}

-f, --skip-fields=N avoid comparing the first N fields

--group[=METHOD] show all items, separating groups with an empty line METHOD={separate(default),prepend,append,both}

-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 line delimiter is NUL, 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'.

## AUTHOR

Written by Richard M. Stallman and David MacKenzie.

## REPORTING BUGS

GNU coreutils online help: <http://www.gnu.org/software/coreutils/>
Report uniq translation bugs to <http://translationproject.org/team/>

## COPYRIGHT

Copyright © 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

## SEE ALSO

comm(1), join(1), sort(1)

Full documentation at: <http://www.gnu.org/software/coreutils/uniq>
or available locally via: info (aq(coreutils) uniq invocation(aq