NAME

uniq — report or filter out duplicated lines

SYNOPSIS

DESCRIPTION

The uniq utility reads input_file line-by-line and by default filters out repeating lines.

If no input_file is given or if input_file is "-", uniq reads from the standard input. If no output_file is given or if output_file is "-", uniq writes to the standard output.

OPTIONS

The following options are supported:

-c

Prefix lines with how many times they are duplicated.

-d

Only write duplicated lines (count > 1).

-f field_shift

Shift the compared line by field_shift amount of fields, where a field is ⟨blank⟩ separated.

-s byte_shift

Shift the compared lines by byte_shift. If field_shift was also specified, it provides an additional shift.

-u

Only write unique lines (count == 1).

EXIT STATUS

The uniq utility exits 0 on success, and >0 if an error occurs.

STANDARDS

uniq should be compliant with the IEEE Std 1003.1-2024 (“POSIX.1”) specification.

AUTHORS

Haelwenn (lanodan) Monnier <contact+utils@hacktivis.me>