uniq(1) — Linux manual page

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:
       <https://www.gnu.org/software/coreutils/>
       Report any translation bugs to
       <https://translationproject.org/team/>

COPYRIGHT

       Copyright © 2024 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

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

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

COLOPHON

       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-9.5.tar.xz fetched from
       ⟨http://ftp.gnu.org/gnu/coreutils/⟩ on 2024-06-14.  If you
       discover any rendering problems in this HTML version of the page,
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       manual page), send a mail to man-pages@man7.org

GNU coreutils 9.5              March 2024                        UNIQ(1)

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

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