uniq(1) — Linux manual page


UNIQ(1)                       User Commands                      UNIQ(1)

NAME         top

       uniq - report or omit repeated lines

SYNOPSIS         top

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

DESCRIPTION         top

       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

       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

              like -D, but allow separating groups with an empty line;

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

              show all items, separating groups with an empty line;

       -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

              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'.

AUTHOR         top

       Written by Richard M. Stallman and David MacKenzie.

REPORTING BUGS         top

       GNU coreutils online help:
       Report any translation bugs to

COPYRIGHT         top

       Copyright © 2023 Free Software Foundation, Inc.  License GPLv3+:
       GNU GPL version 3 or later <https://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         top

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

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

COLOPHON         top

       This page is part of the coreutils (basic file, shell and text
       manipulation utilities) project.  Information about the project
       can be found at ⟨http://www.gnu.org/software/coreutils/⟩.  If you
       have a bug report for this manual page, see
       ⟨http://www.gnu.org/software/coreutils/⟩.  This page was obtained
       from the tarball coreutils-9.4.tar.xz fetched from
       ⟨http://ftp.gnu.org/gnu/coreutils/⟩ on 2023-12-22.  If you
       discover any rendering problems in this HTML version of the page,
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       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

GNU coreutils 9.4              August 2023                       UNIQ(1)

Pages that refer to this page: comm(1)join(1)sort(1)