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Alphabetical listing for U

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uniq(1)
NAME
  uniq - Removes or lists repeated lines in a file

SYNOPSIS
  Current Syntax

  uniq [-cdu] [-f fields] [-s chars] [input-file [output-file]]

  Obsolescent Syntax

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

  The uniq command reads from the specified input_file, compares adjacent
  lines, removes the second and succeeding occurrences of a line, and writes
  to standard output.

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  uniq:	 XCU5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

OPTIONS
  -c  Precedes each output line with a count of the number of times each line
      appears in the file.  This option supersedes the -d and -u options.

  -d  Displays repeated lines only.

  -f fields
      Ignores the first fields fields on each input line when doing
      comparisons, where fields is a positive decimal integer.	A field is
      the maximal string matched by the basic regular expression:

	   [[:blank:]]*[^[:blank:]]*

      If the fields argument specifies more fields than appear on an input
      line, a null string is used for comparisons.

  -s chars
      Ignores the specified number of characters when doing comparisons.  The
      chars argument is a positive decimal integer.

      If specified with the -f option, the first chars characters after the
      first fields fields are ignored.	If the chars argument specifies more
      characters than remain on an input line, uniq uses a null string for
      comparison.

  -u  Displays unique lines only.

  -fields
      Equivalent to -f fields.	(Obsolescent)

  +chars
      Equivalent to -s chars.  (Obsolescent)

OPERANDS
  input_file
      A pathname for the input file.

      If this operand is omitted or specified as -, then standard input is
      read.

  output_file
      A pathname for the output file.

      If this operand is omitted, then standard output is written.

DESCRIPTION
  The input_file and output_file arguments must be different files.  If the
  input_file operand is not specified, or if it is -, uniq uses standard
  input.

  Repeated lines must be on consecutive lines to be found.  You can arrange
  them with the sort command before processing.

EXAMPLES
  To delete repeated lines in the following file called fruit and save it to
  a file named newfruit, enter:

       uniq fruit newfruit

  The file fruit contains the following lines:

       apples
       apples
       bananas
       cherries
       cherries
       peaches
       pears

  The file newfruit contains the following lines:

       apples
       bananas
       cherries
       peaches
       pears

EXIT STATUS
  The following exit values are returned:

  0   Successful completion.

  >0  An error occurred.

ENVIRONMENT VARIABLES
  The following environment variables affect the execution of uniq:

  LANG
      Provides a default value for the internationalization variables that
      are unset or null. If LANG is unset or null, the corresponding value
      from the default locale is used.	If any of the internationalization
      variables contain an invalid setting, the utility behaves as if none of
      the variables had been defined.

  LC_ALL
      If set to a non-empty string value, overrides the values of all the
      other internationalization variables.

  LC_CTYPE
      Determines the locale for the interpretation of sequences of bytes of
      text data as characters (for example, single-byte as opposed to
      multibyte characters in arguments).

  LC_MESSAGES
      Determines the locale for the format and contents of diagnostic
      messages written to standard error.

  NLSPATH
      Determines the location of message catalogues for the processing of
      LC_MESSAGES.

SEE ALSO
  Commands:  comm(1), sort(1)

  Standards:  standards(5)

Index for Section 1

Alphabetical listing for U

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