uniq



UNIQ(1)                     General Commands Manual                    UNIQ(1)


NAME

     uniq - report or filter out repeated lines in a file


SYNOPSIS

     uniq [-c] [-d | -u] [-f fields] [-s chars] [input_file [output_file]]


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 options are as follows:

     -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 which have duplicates.

     -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, with blanks considered
             part of the following field.  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      Only output lines which are unique.

     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.  A file name of `-' denotes the standard input or
     the standard output (depending on its position on the command line).


ENVIRONMENT

     LC_CTYPE  The character set locale(1).  Determines which groups of bytes
               are treated as characters and which characters are considered
               blank.


EXIT STATUS

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


SEE ALSO

     sort(1)


STANDARDS

     The uniq utility is compliant with the IEEE Std 1003.1-2008 (``POSIX.1'')
     specification.

     The use of -c in conjunction with -d or -u is an extension to that
     specification.

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

OpenBSD 5.9                    December 19, 2015                   OpenBSD 5.9

[Unix Hosting | Open-Source | Contact Us]
[Engineering & Automation | Software Development | Server Applications]