.\"-
.\" Copyright 2003-2005 Colin Percival
.\" All rights reserved
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted providing that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
.\" IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd May 18, 2003
.Dt BSDIFF 1
.Os
.Sh NAME
.Nm bsdiff
.Nd "generate a patch between two binary files"
.Sh SYNOPSIS
.Nm
.Ar oldfile newfile patchfile
.Sh DESCRIPTION
The
.Nm
utility
compares
.Ar oldfile
to
.Ar newfile
and writes to
.Ar patchfile
a binary patch suitable for use by
.Xr bspatch 1 .
When
.Ar oldfile
and
.Ar newfile
are two versions of an executable program, the
patches produced are on average a factor of five smaller
than those produced by any other binary patch tool known
to the author.
.Pp
The
.Nm
utility
uses memory equal to 17 times the size of
.Ar oldfile ,
and requires
an absolute minimum working set size of 8 times the size of
.Ar oldfile .
.Sh SEE ALSO
.Xr bspatch 1
.Sh AUTHORS
.An Colin Percival Aq cperciva@FreeBSD.org
.Sh BUGS
The
.Nm
utility does not store the hashes of
.Ar oldfile
or
.Ar newfile
in
.Ar patchfile .
As a result, it is possible to apply a patch to the wrong file; this
will usually produce garbage.
It is recommended that users of
.Nm
store the hashes of
.Ar oldfile
and
.Ar newfile
and compare against them before and after applying
.Ar patchfile .