usr/src/usr.bin/uniq/uniq.1

.\" Copyright (c) 1991, 1993
.\"     The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Institute of Electrical and Electronics Engineers, Inc.
.\"
.\" %sccs.include.redist.roff%
.\"
.\"     @(#)uniq.1      8.1 (Berkeley) %G%
.\"
.Dd
.Dt UNIQ 1
.Os
.Sh NAME
.Nm uniq
.Nd report or filter out repeated lines in a file
.Sh SYNOPSIS
.Nm uniq
.Op Fl c | Fl d | Fl u
.Op Fl f Ar fields
.Op Fl s Ar chars
.Oo
.Ar input_file
.Op Ar output_file
.Oc
.Sh DESCRIPTION
The
.Nm 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.
.Pp
The following options are available:
.Bl -tag -width Ds
.It Fl c
Precede each output line with the count of the number of times the line
occurred in the input, followed by a single space.
.It Fl d
Don't output lines that are not repeated in the input.
.It Fl f Ar fields
Ignore the first
.Ar 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.
.It Fl s Ar chars
Ignore the first
.Ar chars
characters in each input line when doing comparisons.
If specified in conjunction with the
.Fl f
option, the first
.Ar chars
characters after the first
.Ar fields
fields will be ignored.
Character numbers are one based, i.e. the first character is character one.
.It Fl u
Don't output lines that are repeated in the input.
.\".It Fl Ns Ar n
.\"(Deprecated; replaced by
.\".Fl f ) .
.\"Ignore the first n
.\"fields on each input line when doing comparisons,
.\"where n is a number.
.\"A field is a string of non-blank
.\"characters separated from adjacent fields
.\"by blanks.
.\".It Cm \&\(pl Ns Ar n
.\"(Deprecated; replaced by
.\".Fl s ) .
.\"Ignore the first
.\".Ar m
.\"characters when doing comparisons, where
.\".Ar m
.\"is a
.\"number.
.El
.Pp
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.
.Pp
The
.Nm uniq
utility exits 0 on success, and >0 if an error occurs.
.Sh COMPATIBILITY
The historic
.Cm \&\(pl Ns Ar number
and
.Fl Ns Ar number
options have been deprecated but are still supported in this implementation.
.Sh SEE ALSO
.Xr sort 1
.Sh STANDARDS
The
.Nm uniq
utility is expected to be
.St -p1003.2
compatible.