NAME

uniq — report or filter out duplicated lines

SYNOPSIS

uniq [-c|-d|-u] [-f field_shift] [-s byte_shift] [input_file [output_file]]

The uniq utility reads file1 and file2 line-by-line and by default filters out repeating lines.

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).

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

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

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