1.\"	$MirOS: src/bin/cat/cat.1,v 1.2 2012/05/20 15:31:59 tg Exp $
2.\"	$OpenBSD: cat.1,v 1.25 2004/07/02 10:28:34 jmc Exp $
3.\"	$NetBSD: cat.1,v 1.12 1995/09/27 05:38:55 cgd Exp $
4.\"
5.\" Copyright (c) 1989, 1990, 1993
6.\"	The Regents of the University of California.  All rights reserved.
7.\"
8.\" This code is derived from software contributed to Berkeley by
9.\" the Institute of Electrical and Electronics Engineers, Inc.
10.\"
11.\" Redistribution and use in source and binary forms, with or without
12.\" modification, are permitted provided that the following conditions
13.\" are met:
14.\" 1. Redistributions of source code must retain the above copyright
15.\"    notice, this list of conditions and the following disclaimer.
16.\" 2. Redistributions in binary form must reproduce the above copyright
17.\"    notice, this list of conditions and the following disclaimer in the
18.\"    documentation and/or other materials provided with the distribution.
19.\" 3. Neither the name of the University nor the names of its contributors
20.\"    may be used to endorse or promote products derived from this software
21.\"    without specific prior written permission.
22.\"
23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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34.\"
35.\"     @(#)cat.1	8.3 (Berkeley) 5/2/95
36.\"
37.Dd $Mdocdate: May 20 2012 $
38.Dt CAT 1
39.Os
40.Sh NAME
41.Nm cat
42.Nd concatenate and print files
43.Sh SYNOPSIS
44.Nm cat
45.Op Fl belnstuv
46.Op Ar
47.Sh DESCRIPTION
48The
49.Nm
50utility reads files sequentially, writing them to the standard output.
51The
52.Ar file
53operands are processed in command-line order.
54If
55.Ar file
56is a single dash
57.Pq Sq \&-
58or absent,
59.Nm
60reads from the standard input.
61.Pp
62The options are as follows:
63.Bl -tag -width Ds
64.It Fl b
65Implies the
66.Fl n
67option but doesn't count blank lines.
68.It Fl e
69Implies the
70.Fl v
71option and also prints a dollar sign
72.Pq Ql \&$
73at the end of each line.
74.It Fl l
75Set an exclusive advisory lock on the standard output file descriptor.
76This lock is set using
77.Xr fcntl 2
78with the
79.Dv F_SETLKW
80command.
81If the output file is already locked,
82.Nm
83will block until the lock is acquired.
84.It Fl n
85Number the output lines, starting at 1.
86.It Fl s
87Squeeze multiple adjacent empty lines, causing the output to be
88single spaced.
89.It Fl t
90Implies the
91.Fl v
92option and also prints tab characters as
93.Ql ^I .
94.It Fl u
95The output is guaranteed to be unbuffered (see
96.Xr setbuf 3 ) .
97.It Fl v
98Displays non-printing characters so they are visible.
99Control characters print as
100.Ql ^X
101for control-X, with the exception of the tab and EOL characters,
102which are displayed normally.
103The tab character, control-I, can be made visible via the
104.Fl t
105option.
106The
107.Tn DEL
108character (octal 0177) prints as
109.Ql ^? .
110.Pf Non- Ns Tn ASCII
111characters (with the high bit set) are printed as
112.Ql M-
113(for meta) followed by the character for the low 7 bits.
114.El
115.Pp
116The
117.Nm
118utility exits 0 on success or >0 if an error occurred.
119.Sh EXAMPLES
120Print the contents of
121.Ar file1
122to the standard output:
123.Pp
124.Dl $ cat file1
125.Pp
126Sequentially print the contents of
127.Ar file1
128and
129.Ar file2
130to the file
131.Ar file3 ,
132truncating
133.Ar file3
134if it already exists.
135See the manual page for your shell (e.g.,
136.Xr sh 1 )
137for more information on redirection.
138.Pp
139.Dl $ cat file1 file2 > file3
140.Pp
141Print the contents of
142.Ar file1 ,
143print data it receives from the standard input until it receives an
144.Dv EOF
145.Pq Sq ^D
146character, print the contents of
147.Ar file2 ,
148read and output contents of the standard input again, then finally output
149the contents of
150.Ar file3 .
151Note that if the standard input referred to a file, the second dash
152on the command-line would have no effect, since the entire contents of the file
153would have already been read and printed by
154.Nm
155when it encountered the first
156.Ql \&-
157operand.
158.Pp
159.Dl $ cat file1 - file2 - file3
160.Sh SEE ALSO
161.Xr head 1 ,
162.Xr less 1 ,
163.Xr more 1 ,
164.Xr pr 1 ,
165.Xr sh 1 ,
166.Xr tail 1 ,
167.Xr vis 1 ,
168.Xr fcntl 2 ,
169.Xr setbuf 3
170.Rs
171.%A Rob Pike
172.%T "UNIX Style, or cat -v Considered Harmful"
173.%J "USENIX Summer Conference Proceedings"
174.%D 1983
175.Re
176.Sh STANDARDS
177The
178.Nm
179utility is compliant with the
180.St -p1003.2-92
181specification.
182.Pp
183The flags
184.Op Fl belnstv
185are extensions to the specification.
186.Sh HISTORY
187A
188.Nm
189utility appeared in
190.At v1 .
191The
192.Fl l
193option was added from
194.Nx
195in
196.Mx 11 .
197.Sh BUGS
198Because of the shell language mechanism used to perform output
199redirection, the command
200.Ic cat file1 file2 > file1
201will cause the original data in
202.Ar file1
203to be destroyed!
204