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UNIQ(1)                   BSD General Commands Manual                  UNIQ(1)

NAME
     uniq -- report or filter out repeated lines in a file

SYNOPSIS
     uniq [-c | -d | -u] [-i] [-f num] [-s chars] [input_file [output_file]]

DESCRIPTION
     The uniq utility reads the specified input_file comparing adjacent lines, and writes a copy of each
     unique input line to the output_file.  If input_file is a single dash (`-') or absent, the standard
     input is read.  If output_file is absent, standard output is used for output.  The second and succeed-ing succeeding
     ing 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 single space.

     -d      Only output lines that are repeated in the input.

     -f num  Ignore the first num 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 num fields will be
             ignored.  Character numbers are one based, i.e., the first character is character one.

     -u      Only output lines that are not repeated in the input.

     -i      Case insensitive comparison of lines.

ENVIRONMENT
     The LANG, LC_ALL, LC_COLLATE and LC_CTYPE environment variables affect the execution of uniq as
     described in environ(7).

EXIT STATUS
     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 implemen-tation. implementation.
     tation.

SEE ALSO
     sort(1)

STANDARDS
     The uniq utility conforms to IEEE Std 1003.1-2001 (``POSIX.1'') as amended by Cor. 1-2002.

HISTORY
     A uniq command appeared in Version 3 AT&T UNIX.

BSD                              July 3, 2004                              BSD

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