NAME

uniq − report repeated lines in a file

SYNOPSIS

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

DESCRIPTION

uniq reads the input file comparing adjacent lines.  In the normal case, the second and succeeding copies of repeated lines are removed; the remainder is written on the output file.  Input and output should always be different.  Note that repeated lines must be adjacent in order to be found; see sort(1). If the −u flag is used, just the lines that are not repeated in the original 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 non-space, non-tab characters separated by tabs and spaces from its neighbors. 

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

SEE ALSO

comm(1), sort(1). 

September 02, 1992