uniq

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.

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

COPYRIGHT
       Copyright (C) 2018 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 at: <https://www.gnu.org/software/coreutils/uniq>
       or available locally via: info '(coreutils) uniq invocation'

GNU coreutils 8.30              September 2019                         UNIQ(1)