Finally (at least for now), we'll look at the
uniq program. When
sorting data, you will often end up with duplicate lines, lines that
are identical. Usually, all you need is one instance of each line.
This is where
uniq comes in. The
uniq program reads its
standard input, which it expects to be sorted. It only prints out one
copy of each duplicated line. It does have several options. Later on,
we'll use the `-c' option, which prints each unique line, preceded
by a count of the number of times that line occurred in the input.