xref: /freebsd/usr.bin/uniq/uniq.1 (revision b0d29bc47dba79f6f38e67eabadfb4b32ffd9390)
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31.\"     From: @(#)uniq.1	8.1 (Berkeley) 6/6/93
32.\" $FreeBSD$
33.\"
34.Dd December 15, 2019
35.Dt UNIQ 1
36.Os
37.Sh NAME
38.Nm uniq
39.Nd report or filter out repeated lines in a file
40.Sh SYNOPSIS
41.Nm
42.Op Fl c | Fl d | Fl D | Fl u
43.Op Fl i
44.Op Fl f Ar num
45.Op Fl s Ar chars
46.Oo
47.Ar input_file
48.Op Ar output_file
49.Oc
50.Sh DESCRIPTION
51The
52.Nm
53utility reads the specified
54.Ar input_file
55comparing adjacent lines, and writes a copy of each unique input line to
56the
57.Ar output_file .
58If
59.Ar input_file
60is a single dash
61.Pq Sq Fl
62or absent, the standard input is read.
63If
64.Ar output_file
65is absent, standard output is used for output.
66The second and succeeding copies of identical adjacent input lines are
67not written.
68Repeated lines in the input will not be detected if they are not adjacent,
69so it may be necessary to sort the files first.
70.Pp
71The following options are available:
72.Bl -tag -width Ds
73.It Fl c , Fl -count
74Precede each output line with the count of the number of times the line
75occurred in the input, followed by a single space.
76.It Fl d , Fl -repeated
77Output a single copy of each line that is repeated in the input.
78.It Fl D , Fl -all-repeated Op Ar septype
79Output all lines that are repeated (like
80.Fl d ,
81but each copy of the repeated line is written).
82The optional
83.Ar septype
84argument controls how to separate groups of repeated lines in the output;
85it must be one of the following values:
86.Pp
87.Bl -tag -compact -width separate
88.It none
89Do not separate groups of lines (this is the default).
90.It prepend
91Output an empty line before each group of lines.
92.It separate
93Output an empty line after each group of lines.
94.El
95.It Fl f Ar num , Fl -skip-fields Ar num
96Ignore the first
97.Ar num
98fields in each input line when doing comparisons.
99A field is a string of non-blank characters separated from adjacent fields
100by blanks.
101Field numbers are one based, i.e., the first field is field one.
102.It Fl i , Fl -ignore-case
103Case insensitive comparison of lines.
104.It Fl s Ar chars , Fl -skip-chars Ar chars
105Ignore the first
106.Ar chars
107characters in each input line when doing comparisons.
108If specified in conjunction with the
109.Fl f , Fl -unique
110option, the first
111.Ar chars
112characters after the first
113.Ar num
114fields will be ignored.
115Character numbers are one based, i.e., the first character is character one.
116.It Fl u , Fl -unique
117Only output lines that are not repeated in the input.
118.\".It Fl Ns Ar n
119.\"(Deprecated; replaced by
120.\".Fl f ) .
121.\"Ignore the first n
122.\"fields on each input line when doing comparisons,
123.\"where n is a number.
124.\"A field is a string of non-blank
125.\"characters separated from adjacent fields
126.\"by blanks.
127.\".It Cm \&\(pl Ns Ar n
128.\"(Deprecated; replaced by
129.\".Fl s ) .
130.\"Ignore the first
131.\".Ar m
132.\"characters when doing comparisons, where
133.\".Ar m
134.\"is a
135.\"number.
136.El
137.Sh ENVIRONMENT
138The
139.Ev LANG ,
140.Ev LC_ALL ,
141.Ev LC_COLLATE
142and
143.Ev LC_CTYPE
144environment variables affect the execution of
145.Nm
146as described in
147.Xr environ 7 .
148.Sh EXIT STATUS
149.Ex -std
150.Sh COMPATIBILITY
151The historic
152.Cm \&\(pl Ns Ar number
153and
154.Fl Ns Ar number
155options have been deprecated but are still supported in this implementation.
156.Sh SEE ALSO
157.Xr sort 1
158.Sh STANDARDS
159The
160.Nm
161utility conforms to
162.St -p1003.1-2001
163as amended by Cor.\& 1-2002.
164.Sh HISTORY
165A
166.Nm
167command appeared in
168.At v3 .
169