uniq [-count] [<colid-list>]
Eliminates adjacent rows which have the same values. If used with no arguments, then any row which has identical values to its predecessor is removed.
<colid-list> parameter is given
then only the values in the specified columns must be equal
in order for the row to be removed.
-count flag is given, then an additional
column with the name DupCount will be
prepended to the table giving a count of the number of duplicated
input rows represented by each output row. A unique row
has a DupCount value of 1.
Syntax for the
<colid-list> argument is described in Section 6.3.