1.\"- 2.\" Copyright (c) 1989, 1990, 1993 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" the Institute of Electrical and Electronics Engineers, Inc. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 3. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.Dd January 29, 2013 33.Dt CAT 1 34.Os 35.Sh NAME 36.Nm cat 37.Nd concatenate and print files 38.Sh SYNOPSIS 39.Nm 40.Op Fl belnstuv 41.Op Ar 42.Sh DESCRIPTION 43The 44.Nm 45utility reads files sequentially, writing them to the standard output. 46The 47.Ar file 48operands are processed in command-line order. 49If 50.Ar file 51is a single dash 52.Pq Sq Fl 53or absent, 54.Nm 55reads from the standard input. 56If 57.Ar file 58is a 59.Ux 60domain socket, 61.Nm 62connects to it and then reads it until 63.Dv EOF . 64This complements the 65.Ux 66domain binding capability available in 67.Xr inetd 8 . 68.Pp 69The options are as follows: 70.Bl -tag -width indent 71.It Fl b 72Number the non-blank output lines, starting at 1. 73.It Fl e 74Display non-printing characters (see the 75.Fl v 76option), and display a dollar sign 77.Pq Ql \&$ 78at the end of each line. 79.It Fl l 80Set an exclusive advisory lock on the standard output file descriptor. 81This lock is set using 82.Xr fcntl 2 83with the 84.Dv F_SETLKW 85command. 86If the output file is already locked, 87.Nm 88will block until the lock is acquired. 89.It Fl n 90Number the output lines, starting at 1. 91.It Fl s 92Squeeze multiple adjacent empty lines, causing the output to be 93single spaced. 94.It Fl t 95Display non-printing characters (see the 96.Fl v 97option), and display tab characters as 98.Ql ^I . 99.It Fl u 100Disable output buffering. 101.It Fl v 102Display non-printing characters so they are visible. 103Control characters print as 104.Ql ^X 105for control-X; the delete 106character (octal 0177) prints as 107.Ql ^? . 108.Pf Non- Tn ASCII 109characters (with the high bit set) are printed as 110.Ql M- 111(for meta) followed by the character for the low 7 bits. 112.El 113.Sh EXIT STATUS 114.Ex -std 115.Sh EXAMPLES 116The command: 117.Pp 118.Dl "cat file1" 119.Pp 120will print the contents of 121.Pa file1 122to the standard output. 123.Pp 124The command: 125.Pp 126.Dl "cat file1 file2 > file3" 127.Pp 128will sequentially print the contents of 129.Pa file1 130and 131.Pa file2 132to the file 133.Pa file3 , 134truncating 135.Pa file3 136if it already exists. 137See the manual page for your shell (e.g., 138.Xr sh 1 ) 139for more information on redirection. 140.Pp 141The command: 142.Pp 143.Dl "cat file1 - file2 - file3" 144.Pp 145will print the contents of 146.Pa file1 , 147print data it receives from the standard input until it receives an 148.Dv EOF 149.Pq Sq ^D 150character, print the contents of 151.Pa file2 , 152read and output contents of the standard input again, then finally output 153the contents of 154.Pa file3 . 155Note that if the standard input refers to a file, the second dash 156on the command-line would have no effect, since the entire contents of the file 157would have already been read and printed by 158.Nm 159when it encountered the first 160.Sq Fl 161operand. 162.Sh SEE ALSO 163.Xr head 1 , 164.Xr more 1 , 165.Xr pr 1 , 166.Xr sh 1 , 167.Xr tail 1 , 168.Xr vis 1 , 169.Xr zcat 1 , 170.Xr fcntl 2 , 171.Xr setbuf 3 172.Rs 173.%A Rob Pike 174.%T "UNIX Style, or cat -v Considered Harmful" 175.%J "USENIX Summer Conference Proceedings" 176.%D 1983 177.Re 178.Sh STANDARDS 179The 180.Nm 181utility is compliant with the 182.St -p1003.2-92 183specification. 184.Pp 185The flags 186.Op Fl belnstv 187are extensions to the specification. 188.Sh HISTORY 189A 190.Nm 191utility appeared in 192.At v1 . 193.An Dennis Ritchie 194designed and wrote the first man page. 195It appears to have been for 196.Nm . 197.Sh BUGS 198Because of the shell language mechanism used to perform output 199redirection, the command 200.Dq Li cat file1 file2 > file1 201will cause the original data in 202.Pa file1 203to be destroyed! 204.Pp 205The 206.Nm 207utility does not recognize multibyte characters when the 208.Fl t 209or 210.Fl v 211option is in effect. 212