uniq(C)                         19 June 1992                         uniq(C)


 Name

    uniq - report repeated lines in a file

 Syntax

    uniq [ -udc [ +n ] [ -n ] ] [ input [ output ] ]

 Description

    The uniq command reads the input file and compares adjacent lines.  In
    the normal case, the second and succeeding copies of repeated lines are
    removed and the lines are compared according to the collating sequence
    defined by the current locale (see locale(M)); the remainder is written
    to the output file.  input and output should always be different.  Note
    that repeated lines must be adjacent in order to be found; see sort(C).
    If the -u flag is used, just the lines that are not repeated in the ori-
    ginal file are output.  The -d option specifies that one copy of just the
    repeated lines is to be written.  The normal mode output is the union of
    the -u and -d mode outputs.

    The -c option supersedes -u and -d and generates an output report in
    default style but with each line preceded by a count of the number of
    times it occurred.

    The n arguments specify skipping an initial portion of each line in the
    comparison:

    -n    The first n fields together with any blanks before each are
          ignored.  A field is defined as a string of nonspace, nontab char-
          acters separated by tabs and spaces from its neighbors.

    +n    The first n characters are ignored.  Fields are skipped before
          characters.


 See also

    comm(C), sort(C)

 Standards conformance

    uniq is conformant with:

    AT&T SVID Issue 2;
    and X/Open Portability Guide, Issue 3, 1989.