uniq - report or filter out repeated lines in a file
uniq [-c | -d | -u] [-f fields] [-s chars] [input_file
[output_file]]
The uniq utility reads the standard input comparing adjacent
lines and
writes a copy of each unique input line to the standard output. The second
and succeeding copies of identical adjacent input lines
are not written.
Repeated lines in the input will not be detected if
they are not
adjacent, so it may be necessary to sort the files first.
The options are as follows:
-c Precede each output line with the count of the number of times
the line occurred in the input, followed by a single
space.
-d Only output lines which have duplicates.
-f fields
Ignore the first fields in each input line when doing comparisons.
A field is a string of non-blank characters
separated
from adjacent fields by blanks. Field numbers are
one based,
i.e., the first field is field one.
-s chars
Ignore the first chars characters in each input line
when doing
comparisons. If specified in conjunction with the
-f option, the
first chars characters after the first fields fields
will be ignored.
Character numbers are one based, i.e., the
first character
is character one.
-u Only output lines which are unique.
If additional arguments are specified on the command line,
the first such
argument is used as the name of an input file, the second is
used as the
name of an output file. A file name of `-' denotes the
standard input or
the standard output (depending on its position on the command line).
The uniq utility exits 0 on success or >0 if an error occurred.
sort(1)
The historic +number and -number options have been deprecated but are
still supported in this implementation.
The uniq utility is expected to be IEEE Std 1003.2
(``POSIX.2'') compatible.
OpenBSD 3.6 December 8, 2002
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