1.\" $OpenBSD: cat.1,v 1.37 2024/08/01 14:08:07 jmc Exp $ 2.\" $NetBSD: cat.1,v 1.12 1995/09/27 05:38:55 cgd Exp $ 3.\" 4.\" Copyright (c) 1989, 1990, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" This code is derived from software contributed to Berkeley by 8.\" the Institute of Electrical and Electronics Engineers, Inc. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)cat.1 8.3 (Berkeley) 5/2/95 35.\" 36.Dd $Mdocdate: August 1 2024 $ 37.Dt CAT 1 38.Os 39.Sh NAME 40.Nm cat 41.Nd concatenate and print files 42.Sh SYNOPSIS 43.Nm cat 44.Op Fl benstuv 45.Op Ar 46.Sh DESCRIPTION 47The 48.Nm 49utility reads files sequentially, writing them to the standard output. 50The 51.Ar file 52operands are processed in command-line order. 53If 54.Ar file 55is a single dash 56.Pq Sq - 57or absent, 58.Nm 59reads from the standard input. 60.Pp 61The options are as follows: 62.Bl -tag -width Ds 63.It Fl b 64Number the lines, but don't count blank lines. 65.It Fl e 66Print a dollar sign 67.Pq Ql \&$ 68at the end of each line. 69Implies the 70.Fl v 71option to display non-printing characters. 72.It Fl n 73Number the output lines, starting at 1. 74.It Fl s 75Squeeze multiple adjacent empty lines, causing the output to be 76single spaced. 77.It Fl t 78Print tab characters as 79.Ql ^I . 80Implies the 81.Fl v 82option to display non-printing characters. 83.It Fl u 84The output is guaranteed to be unbuffered (see 85.Xr setvbuf 3 ) . 86.It Fl v 87Displays non-printing characters so they are visible. 88Control characters print as 89.Ql ^X 90for control-X, with the exception of the tab and EOL characters, 91which are displayed normally. 92The DEL character (octal 0177) prints as 93.Ql ^? . 94Non-ASCII characters (with the high bit set) are printed as 95.Ql M- 96(for meta) followed by the character for the low 7 bits. 97.El 98.Sh EXIT STATUS 99.Ex -std cat 100.Sh EXAMPLES 101Print the contents of 102.Ar file1 103to the standard output: 104.Pp 105.Dl $ cat file1 106.Pp 107Sequentially print the contents of 108.Ar file1 109and 110.Ar file2 111to the file 112.Ar file3 , 113truncating 114.Ar file3 115if it already exists. 116See the manual page for your shell (e.g., 117.Xr sh 1 ) 118for more information on redirection. 119.Pp 120.Dl $ cat file1 file2 > file3 121.Pp 122Print the contents of 123.Ar file1 , 124print data it receives from the standard input until it receives an 125.Dv EOF 126.Pq Sq ^D 127character, print the contents of 128.Ar file2 , 129read and output contents of the standard input again, then finally output 130the contents of 131.Ar file3 . 132Note that if the standard input referred to a file, the second dash 133on the command line would have no effect, since the entire contents of the file 134would have already been read and printed by 135.Nm 136when it encountered the first 137.Ql \&- 138operand. 139.Pp 140.Dl $ cat file1 - file2 - file3 141.Sh SEE ALSO 142.Xr head 1 , 143.Xr less 1 , 144.Xr more 1 , 145.Xr pr 1 , 146.Xr sh 1 , 147.Xr tail 1 , 148.Xr vis 1 , 149.Xr setvbuf 3 150.Rs 151.%A Rob Pike 152.%T "UNIX Style, or cat -v Considered Harmful" 153.%J "USENIX Summer Conference Proceedings" 154.%D 1983 155.Re 156.Sh STANDARDS 157The 158.Nm 159utility is compliant with the 160.St -p1003.1-2024 161specification. 162.Pp 163The flags 164.Op Fl benstv 165are extensions to that specification. 166.Sh HISTORY 167A 168.Nm 169utility appeared in 170.At v1 . 171.Sh CAVEATS 172Because of the shell language mechanism used to perform output 173redirection, the following command will cause the original data in 174.Ar file1 175to be destroyed: 176.Pp 177.Dl $ cat file1 file2 > file1 178.Pp 179To append 180.Ar file2 181to 182.Ar file1 , 183instead use: 184.Pp 185.Dl $ cat file2 >> file1 186