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1 .\"-
2 .\" Copyright (c) 1989, 1990, 1993
3 .\" The Regents of the University of California. All rights reserved.
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5 .\" This code is derived from software contributed to Berkeley by
6 .\" the Institute of Electrical and Electronics Engineers, Inc.
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35 .\"
36 .\" @(#)cat.1 8.3 (Berkeley) 5/2/95
37 .\" $FreeBSD: src/bin/cat/cat.1,v 1.27 2006/12/23 09:25:23 ru Exp $
38 .\" $DragonFly: src/bin/cat/cat.1,v 1.6 2007/02/04 21:08:28 pavalos Exp $
39 .\"
40 .Dd March 21, 2004
41 .Dt CAT 1
42 .Os
43 .Sh NAME
44 .Nm cat
45 .Nd concatenate and print files
46 .Sh SYNOPSIS
47 .Nm
48 .Op Fl benstuv
49 .Op Ar
50 .Sh DESCRIPTION
51 The
52 .Nm
53 utility reads files sequentially, writing them to the standard output.
54 The
55 .Ar file
56 operands are processed in command-line order.
57 If
58 .Ar file
59 is a single dash
60 .Pq Sq Fl
61 or absent,
62 .Nm
63 reads from the standard input.
64 If
65 .Ar file
66 is a
67 .Ux
68 domain socket,
69 .Nm
70 connects to it and then reads it until
71 .Dv EOF .
72 This complements the
73 .Ux
74 domain binding capability available in
75 .Xr inetd 8 .
76 .Pp
77 The options are as follows:
78 .Bl -tag -width indent
79 .It Fl b
80 Number the non-empty output lines, starting at 1.
81 .It Fl e
82 Display non-printing characters (see the
83 .Fl v
84 option), and display a dollar sign
85 .Pq Ql \&$
86 at the end of each line.
87 .It Fl n
88 Number the output lines, starting at 1.
89 .It Fl s
90 Squeeze multiple adjacent empty lines, causing the output to be
91 single spaced.
92 .It Fl t
93 Display non-printing characters (see the
94 .Fl v
95 option), and display tab characters as
96 .Ql ^I .
97 .It Fl u
98 Disable output buffering.
99 .It Fl v
100 Display non-printing characters so they are visible.
101 Control characters print as
102 .Ql ^X
103 for control-X; the delete
104 character (octal 0177) prints as
105 .Ql ^? .
106 .Pf Non- Tn ASCII
107 characters (with the high bit set) are printed as
108 .Ql M-
109 (for meta) followed by the character for the low 7 bits.
110 .El
111 .Sh EXIT STATUS
112 .Ex -std
113 .Sh EXAMPLES
114 The command:
115 .Pp
116 .Dl "cat file1"
117 .Pp
118 will print the contents of
119 .Pa file1
120 to the standard output.
121 .Pp
122 The command:
123 .Pp
124 .Dl "cat file1 file2 > file3"
125 .Pp
126 will sequentially print the contents of
127 .Pa file1
128 and
129 .Pa file2
130 to the file
131 .Pa file3 ,
132 truncating
133 .Pa file3
134 if it already exists.
135 See the manual page for your shell (i.e.,
136 .Xr sh 1 )
137 for more information on redirection.
138 .Pp
139 The command:
140 .Pp
141 .Dl "cat file1 - file2 - file3"
142 .Pp
143 will print the contents of
144 .Pa file1 ,
145 print data it receives from the standard input until it receives an
146 .Dv EOF
147 .Pq Sq ^D
148 character, print the contents of
149 .Pa file2 ,
150 read and output contents of the standard input again, then finally output
151 the contents of
152 .Pa file3 .
153 Note that if the standard input referred to a file, the second dash
154 on the command-line would have no effect, since the entire contents of the file
155 would have already been read and printed by
156 .Nm
157 when it encountered the first
158 .Sq Fl
159 operand.
160 .Sh SEE ALSO
161 .Xr head 1 ,
162 .Xr more 1 ,
163 .Xr pr 1 ,
164 .Xr sh 1 ,
165 .Xr tail 1 ,
166 .Xr vis 1 ,
167 .Xr zcat 1 ,
168 .Xr setbuf 3
169 .Rs
170 .%A Rob Pike
171 .%T "UNIX Style, or cat -v Considered Harmful"
172 .%J "USENIX Summer Conference Proceedings"
173 .%D 1983
174 .Re
175 .Sh STANDARDS
176 The
177 .Nm
178 utility conforms to
179 .St -p1003.2-92
180 and
181 .St -p1003.1-2004 .
182 .Pp
183 The flags
184 .Op Fl benstv
185 are extensions to the specification.
186 .Sh HISTORY
187 A
188 .Nm
189 utility appeared in
190 .At v1 .
191 .An Dennis Ritchie
192 designed and wrote the first man page.
193 It appears to have been
194 .Xr cat 1 .
195 .Sh BUGS
196 Because of the shell language mechanism used to perform output
197 redirection, the command
198 .Dq Li cat file1 file2 > file1
199 will cause the original data in
200 .Pa file1
201 to be destroyed!
202 .Pp
203 The
204 .Nm
205 utility does not recognize multibyte characters when the
206 .Fl t
207 or
208 .Fl v
209 option is in effect.