xref: /freebsd/usr.bin/uniq/uniq.1 (revision 9336e0699bda8a301cd2bfa37106b6ec5e32012e)
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35.\"     From: @(#)uniq.1	8.1 (Berkeley) 6/6/93
36.\" $FreeBSD$
37.\"
38.Dd July 3, 2004
39.Dt UNIQ 1
40.Os
41.Sh NAME
42.Nm uniq
43.Nd report or filter out repeated lines in a file
44.Sh SYNOPSIS
45.Nm
46.Op Fl c | Fl d | Fl u
47.Op Fl i
48.Op Fl f Ar num
49.Op Fl s Ar chars
50.Oo
51.Ar input_file
52.Op Ar output_file
53.Oc
54.Sh DESCRIPTION
55The
56.Nm
57utility reads the specified
58.Ar input_file
59comparing adjacent lines, and writes a copy of each unique input line to
60the
61.Ar output_file .
62If
63.Ar input_file
64is a single dash
65.Pq Sq Fl
66or absent, the standard input is read.
67If
68.Ar output_file
69is absent, standard output is used for output.
70The second and succeeding copies of identical adjacent input lines are
71not written.
72Repeated lines in the input will not be detected if they are not adjacent,
73so it may be necessary to sort the files first.
74.Pp
75The following options are available:
76.Bl -tag -width Ds
77.It Fl c
78Precede each output line with the count of the number of times the line
79occurred in the input, followed by a single space.
80.It Fl d
81Only output lines that are repeated in the input.
82.It Fl f Ar num
83Ignore the first
84.Ar num
85fields in each input line when doing comparisons.
86A field is a string of non-blank characters separated from adjacent fields
87by blanks.
88Field numbers are one based, i.e., the first field is field one.
89.It Fl s Ar chars
90Ignore the first
91.Ar chars
92characters in each input line when doing comparisons.
93If specified in conjunction with the
94.Fl f
95option, the first
96.Ar chars
97characters after the first
98.Ar num
99fields will be ignored.
100Character numbers are one based, i.e., the first character is character one.
101.It Fl u
102Only output lines that are not repeated in the input.
103.It Fl i
104Case insensitive comparison of lines.
105.\".It Fl Ns Ar n
106.\"(Deprecated; replaced by
107.\".Fl f ) .
108.\"Ignore the first n
109.\"fields on each input line when doing comparisons,
110.\"where n is a number.
111.\"A field is a string of non-blank
112.\"characters separated from adjacent fields
113.\"by blanks.
114.\".It Cm \&\(pl Ns Ar n
115.\"(Deprecated; replaced by
116.\".Fl s ) .
117.\"Ignore the first
118.\".Ar m
119.\"characters when doing comparisons, where
120.\".Ar m
121.\"is a
122.\"number.
123.El
124.Sh ENVIRONMENT
125The
126.Ev LANG ,
127.Ev LC_ALL ,
128.Ev LC_COLLATE
129and
130.Ev LC_CTYPE
131environment variables affect the execution of
132.Nm
133as described in
134.Xr environ 7 .
135.Sh EXIT STATUS
136.Ex -std
137.Sh COMPATIBILITY
138The historic
139.Cm \&\(pl Ns Ar number
140and
141.Fl Ns Ar number
142options have been deprecated but are still supported in this implementation.
143.Sh SEE ALSO
144.Xr sort 1
145.Sh STANDARDS
146The
147.Nm
148utility conforms to
149.St -p1003.1-2001
150as amended by Cor.\& 1-2002.
151.Sh HISTORY
152A
153.Nm
154command appeared in
155.At v3 .
156.Sh BUGS
157Input lines are limited to
158.Dv LINE_MAX
159(2048) bytes in length.
160