term% cat index.txt UNIQ(1) General Commands Manual UNIQ(1)
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. 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 ig‐
nored. 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
sort(1), comm(1)
UNIQ(1)