UNIQ(1)                    Commands and Applications                   UNIQ(1)




NAME

       uniq - report or filter out repeated lines in a file


SYNOPSIS

       uniq [-c | -du] [-i] [-f fields] [-s chars] [input [output]]

       Obsolescent:

       uniq [-fields] [+chars] [input [output]]


DESCRIPTION

       The uniq utility reads the standard input comparing adjacent lines, and
       writes a copy of each unique input line to the  standard  output.   The
       second  and succeeding copies of identical adjacent input lines are not
       written.  Repeated lines in the input will not be detected if they  are
       not adjacent, so it may be necessary to sort the files first.

       The following options are available:

              -c     Precede  each output line with the count of the number of
                     times the line occurred in the input, followed by a  sin-
                     gle space.

              -d     Print one copy of each repeated line in the input.

              -f fields
                     Ignore  the  first  fields  in each input line when doing
                     comparisons.  A field is a string of non-blank characters
                     separated  from adjacent fields by blanks.  Field numbers
                     are one based, i.e. the first field is field one.

              -s chars
                     Ignore the first chars characters in each input line when
                     doing  comparisons.  If specified in conjunction with the
                     -f option, the first chars  characters  after  the  first
                     fields fields will be ignored.  Character numbers are one
                     based, i.e. the first character is character one.

              -u     Print lines that are not repeated in the input.

              -i     Case insensitive comparison of lines.

       If additional arguments are specified on the command  line,  the  first
       such  argument is used as the name of an input file, the second is used
       as the name of an output file.

       If neither of the options d or u are specified  on  the  command  line,
       uniq  behaves  as  if  both  d and u are set, printing a single copy of
       repeated lines as well as unrepeated lines.

       The uniq utility exits 0 on success, and >0 if an error occurs.


COMPATIBILITY

       The historic +number and -number options have been deprecated  but  are
       still supported in this implementation.


VERSION

       This manual page documents uniq version 2.0.


ATTRIBUTIONS

       This  command was ported from FreeBSD source code for distribution with
       GNO/ME 2.0.6.


HISTORY

       A version of uniq written in 1992 was distributed with earlier releases
       of GNO.


SEE ALSO

       sort(1)


STANDARDS

       The uniq utility is expected to be POSIX-2 compatible.



GNO                              November 1997                         UNIQ(1)

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