NAME
uniq —
report or filter out repeated lines in
a file
SYNOPSIS
uniq |
[-c | -d |
-u] [-i]
[-f num]
[-s chars]
[input_file
[output_file]] |
DESCRIPTION
Theuniq utility reads the specified
input_file comparing adjacent lines, and writes a copy
of each unique input line to the output_file. If
input_file is a single dash
(‘-’) or absent, the standard input is
read. If output_file is absent, standard output is used
for 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 following options are available:
-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 that are repeated in the input.
-fnum- Ignore the first num 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.
-schars- Ignore the first chars characters in each input line
when doing comparisons. If specified in conjunction with the
-foption, the first chars characters after the first num fields will be ignored. Character numbers are one based, i.e., the first character is character one. -u- Only output lines that are not repeated in the input.
-i- Case insensitive comparison of lines.
ENVIRONMENT
The LANG, LC_ALL,
LC_COLLATE and LC_CTYPE
environment variables affect the execution of uniq
as described in
environ(7).
EXIT STATUS
The uniq utility exits 0 on
success, and >0 if an error occurs.
COMPATIBILITY
The historic +number
and -number options have been
deprecated but are still supported in this implementation.
SEE ALSO
STANDARDS
The uniq utility conforms to
IEEE Std 1003.1-2001 (“POSIX.1”) as
amended by Cor. 1-2002.
HISTORY
A uniq command appeared in
Version 3 AT&T UNIX.