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.\" 4. 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.\" @(#)cat.1 8.3 (Berkeley) 5/2/95 33.\" $FreeBSD$ 34.\" 35.Dd January 29, 2013 36.Dt CAT 1 37.Os 38.Sh NAME 39.Nm cat 40.Nd concatenate and print files 41.Sh SYNOPSIS 42.Nm 43.Op Fl belnstuv 44.Op Ar 45.Sh DESCRIPTION 46The 47.Nm 48utility reads files sequentially, writing them to the standard output. 49The 50.Ar file 51operands are processed in command-line order. 52If 53.Ar file 54is a single dash 55.Pq Sq Fl 56or absent, 57.Nm 58reads from the standard input. 59If 60.Ar file 61is a 62.Ux 63domain socket, 64.Nm 65connects to it and then reads it until 66.Dv EOF . 67This complements the 68.Ux 69domain binding capability available in 70.Xr inetd 8 . 71.Pp 72The options are as follows: 73.Bl -tag -width indent 74.It Fl b 75Number the non-blank output lines, starting at 1. 76.It Fl e 77Display non-printing characters (see the 78.Fl v 79option), and display a dollar sign 80.Pq Ql \&$ 81at the end of each line. 82.It Fl l 83Set an exclusive advisory lock on the standard output file descriptor. 84This lock is set using 85.Xr fcntl 2 86with the 87.Dv F_SETLKW 88command. 89If the output file is already locked, 90.Nm 91will block until the lock is acquired. 92.It Fl n 93Number the output lines, starting at 1. 94.It Fl s 95Squeeze multiple adjacent empty lines, causing the output to be 96single spaced. 97.It Fl t 98Display non-printing characters (see the 99.Fl v 100option), and display tab characters as 101.Ql ^I . 102.It Fl u 103Disable output buffering. 104.It Fl v 105Display non-printing characters so they are visible. 106Control characters print as 107.Ql ^X 108for control-X; the delete 109character (octal 0177) prints as 110.Ql ^? . 111.Pf Non- Tn ASCII 112characters (with the high bit set) are printed as 113.Ql M- 114(for meta) followed by the character for the low 7 bits. 115.El 116.Sh EXIT STATUS 117.Ex -std 118.Sh EXAMPLES 119The command: 120.Pp 121.Dl "cat file1" 122.Pp 123will print the contents of 124.Pa file1 125to the standard output. 126.Pp 127The command: 128.Pp 129.Dl "cat file1 file2 > file3" 130.Pp 131will sequentially print the contents of 132.Pa file1 133and 134.Pa file2 135to the file 136.Pa file3 , 137truncating 138.Pa file3 139if it already exists. 140See the manual page for your shell (e.g., 141.Xr sh 1 ) 142for more information on redirection. 143.Pp 144The command: 145.Pp 146.Dl "cat file1 - file2 - file3" 147.Pp 148will print the contents of 149.Pa file1 , 150print data it receives from the standard input until it receives an 151.Dv EOF 152.Pq Sq ^D 153character, print the contents of 154.Pa file2 , 155read and output contents of the standard input again, then finally output 156the contents of 157.Pa file3 . 158Note that if the standard input referred to a file, the second dash 159on the command-line would have no effect, since the entire contents of the file 160would have already been read and printed by 161.Nm 162when it encountered the first 163.Sq Fl 164operand. 165.Sh SEE ALSO 166.Xr head 1 , 167.Xr more 1 , 168.Xr pr 1 , 169.Xr sh 1 , 170.Xr tail 1 , 171.Xr vis 1 , 172.Xr zcat 1 , 173.Xr fcntl 2 , 174.Xr setbuf 3 175.Rs 176.%A Rob Pike 177.%T "UNIX Style, or cat -v Considered Harmful" 178.%J "USENIX Summer Conference Proceedings" 179.%D 1983 180.Re 181.Sh STANDARDS 182The 183.Nm 184utility is compliant with the 185.St -p1003.2-92 186specification. 187.Pp 188The flags 189.Op Fl belnstv 190are extensions to the specification. 191.Sh HISTORY 192A 193.Nm 194utility appeared in 195.At v1 . 196.An Dennis Ritchie 197designed and wrote the first man page. 198It appears to have been 199.Xr cat 1 . 200.Sh BUGS 201Because of the shell language mechanism used to perform output 202redirection, the command 203.Dq Li cat file1 file2 > file1 204will cause the original data in 205.Pa file1 206to be destroyed! 207.Pp 208The 209.Nm 210utility does not recognize multibyte characters when the 211.Fl t 212or 213.Fl v 214option is in effect. 215