|| FreeBSD General Commands Manual
report or filter out repeated lines in a file
|| [ -c | -d | -u][ -i][ -f num][ -s chars][ input_file [ output_file]]
utility reads the specified
comparing adjacent lines, and writes a copy of each unique input line to the
is a single dash (‘
’) or absent, the standard input is read. If
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:
Precede each output line with the count of the number of times the line occurred in the input, followed by a single space.
Only output lines that are repeated in the input.
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.
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
num fields will be ignored. Character numbers are one based, i.e., the first character is character one.
Only output lines that are not repeated in the input.
Case insensitive comparison of lines.
environment variables affect the execution of
as described in
EXIT STATUS The
uniq utility exits 0 on success, and >0 if an error occurs.
COMPATIBILITY The historic
number options have been deprecated but are still supported in this implementation.
uniq utility conforms to IEEE Std 1003.1-2001 (“POSIX.1”) as amended by Cor. 1-2002.
uniq command appeared in Version 3 AT&T UNIX.