1 .\" Copyright (c) 1989, 1990, 1993
2 .\" The Regents of the University of California. All rights reserved.
4 .\" This code is derived from software contributed to Berkeley by
5 .\" the Institute of Electrical and Electronics Engineers, Inc.
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35 .\" @(#)cat.1 8.3 (Berkeley) 5/2/95
36 .\" $FreeBSD: src/bin/cat/cat.1,v 1.10.2.9 2001/12/14 14:22:08 ru Exp $
37 .\" $DragonFly: src/bin/cat/cat.1,v 1.2 2003/06/17 04:22:49 dillon Exp $
39 .Dd September 15, 2001
44 .Nd concatenate and print files
52 utility reads files sequentially, writing them to the standard output.
55 operands are processed in command-line order.
62 reads from the standard input.
69 connects to it and then reads it until
73 domain binding capability available in
76 The options are as follows:
77 .Bl -tag -width indent
79 Number the non-blank output lines, starting at 1.
81 Display non-printing characters (see the
83 option), and display a dollar sign
85 at the end of each line.
87 Number the output lines, starting at 1.
89 Squeeze multiple adjacent empty lines, causing the output to be
92 Display non-printing characters (see the
94 option), and display tab characters as
99 option guarantees that the output is unbuffered.
101 Display non-printing characters so they are visible.
102 Control characters print as
104 for control-X; the delete
105 character (octal 0177) prints as
108 characters (with the high bit set) are printed as
110 (for meta) followed by the character for the low 7 bits.
116 .Bd -literal -offset indent
120 will print the contents of
122 to the standard output.
125 .Bd -literal -offset indent
126 .Ic cat file1 file2 > file3
129 will sequentially print the contents of
137 if it already exists.
138 See the manual page for your shell (i.e.,
140 for more information on redirection.
143 .Bd -literal -offset indent
144 .Ic cat file1 - file2 - file3
147 will print the contents of
149 print data it receives from the standard input until it receives an
152 character, print the contents of
154 read and output contents of the standard input again, then finally output
157 Note that if the standard input referred to a file, the second dash
158 on the command-line would have no effect, since the entire contents of the file
159 would have already been read and printed by
161 when it encountered the first
175 .%T "UNIX Style, or cat -v Considered Harmful"
176 .%J "USENIX Summer Conference Proceedings"
182 utility is compliant with the
188 are extensions to the specification.
195 designed and wrote the first man page.
196 It appears to have been
199 Because of the shell language mechanism used to perform output
200 redirection, the command
201 .Dq Li cat file1 file2 > file1
202 will cause the original data in file1 to be destroyed!