Manual: gnuuniq

UNIQ(1)							User Commands						     UNIQ(1)

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     print all duplicate lines

       --all-repeated[=METHOD]
	      like -D, but allow separating groups 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.

       'uniq'  does  not detect repeated lines unless they are adjacent.  You may want to sort the input first, or use 'sort
       -u' without 'uniq'.

AUTHOR
       Written by Richard M. Stallman and David MacKenzie.

REPORTING BUGS
       GNU coreutils online help: 
       Report any translation bugs to 

SEE ALSO
       comm(1), join(1), sort(1)

       Full documentation 
       or available locally via: info '(coreutils) uniq invocation'

       Packaged by Ubuntu (9.7-3ubuntu2)
       Copyright © 2025 Free Software Foundation, Inc.
       License GPLv3+: GNU GPL version 3 or later .
       This is free software: you are free to change and redistribute it.
       There is NO WARRANTY, to the extent permitted by law.

GNU coreutils 9.7					January 2026						     UNIQ(1)