1.\" Copyright (c) 1987, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)cmp.1 8.1 (Berkeley) 6/6/93 32.\" $FreeBSD$ 33.\" 34.Dd June 20, 2020 35.Dt CMP 1 36.Os 37.Sh NAME 38.Nm cmp 39.Nd compare two files 40.Sh SYNOPSIS 41.Nm 42.Op Fl l | s | x 43.Op Fl hz 44.Ar file1 file2 45.Op Ar skip1 Op Ar skip2 46.Sh DESCRIPTION 47The 48.Nm 49utility compares two files of any type and writes the results 50to the standard output. 51By default, 52.Nm 53is silent if the files are the same; if they differ, the byte 54and line number at which the first difference occurred is reported. 55.Pp 56Bytes and lines are numbered beginning with one. 57.Pp 58The following options are available: 59.Bl -tag -width indent 60.It Fl h 61Do not follow symbolic links. 62.It Fl l , Fl -verbose 63Print the byte number (decimal) and the differing 64byte values (octal) for each difference. 65.It Fl s , Fl -silent , Fl -quiet 66Print nothing for differing files; return exit 67status only. 68.It Fl x 69Like 70.Fl l 71but prints in hexadecimal and using zero as index 72for the first byte in the files. 73.It Fl z 74For regular files compare file sizes first, and fail the comparison if they 75are not equal. 76.El 77.Pp 78The optional arguments 79.Ar skip1 80and 81.Ar skip2 82are the byte offsets from the beginning of 83.Ar file1 84and 85.Ar file2 , 86respectively, where the comparison will begin. 87The offset is decimal by default, but may be expressed as a hexadecimal 88or octal value by preceding it with a leading ``0x'' or ``0''. 89.Sh EXIT STATUS 90The 91.Nm 92utility exits with one of the following values: 93.Bl -tag -width 4n 94.It 0 95The files are identical. 96.It 1 97The files are different; this includes the case 98where one file is identical to the first part of 99the other. 100In the latter case, if the 101.Fl s 102option has not been specified, 103.Nm 104writes to standard error that EOF was reached in the shorter 105file (before any differences were found). 106.It >1 107An error occurred. 108.El 109.Sh EXAMPLES 110Assuming a file named 111.Pa example.txt 112with the following contents: 113.Bd -literal -offset indent 114a 115b 116c 117.Ed 118.Pp 119Compare stdin with 120.Pa example.txt : 121.Bd -literal -offset indent 122$ echo -e "a\\nb\\nc" | cmp - example.txt 123.Ed 124.Pp 125Same as above but introducing a change in the third byte of stdin. 126Show the byte number (decimal) and differing byte (octal): 127.Bd -literal -offset indent 128$ echo -e "a\\nR\\nc" | cmp -l - example.txt 129 3 122 142 130.Ed 131.Pp 132Compare file sizes of 133.Pa example.txt 134and 135.Pa /boot/loader.conf 136and return 1 if they are not equal. 137Note that 138.Fl z 139can only be used with regular files: 140.Bd -literal -offset indent 141$ cmp -z example.txt /boot/loader.conf 142example.txt /boot/loader.conf differ: size 143.Ed 144.Pp 145Compare stdin with 146.Pa example.txt 147omitting the first 4 bytes from stdin and the first 2 bytes from 148.Pa example.txt : 149.Bd -literal -offset indent 150$ echo -e "a\\nR\\nb\\nc" | cmp - example.txt 4 2 151.Ed 152.Sh SEE ALSO 153.Xr diff 1 , 154.Xr diff3 1 155.Sh STANDARDS 156The 157.Nm 158utility is expected to be 159.St -p1003.2 160compatible. 161The 162.Fl h , 163.Fl x , 164and 165.Fl z 166options are extensions to the standard. 167.Sh HISTORY 168A 169.Nm 170command appeared in 171.At v1 . 172