bspatch.1

.\"-
.\" Copyright 2003-2005 Colin Percival
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.\" $FreeBSD: src/usr.bin/bsdiff/bspatch/bspatch.1,v 1.1 2005/08/06 01:59:06 cperciva Exp $
.\"
.Dd May 18, 2003
.Dt BSPATCH 1
.Os FreeBSD
.Sh NAME
.Nm bspatch
.Nd apply a patch built with bsdiff(1)
.Sh SYNOPSIS
.Nm
.Ar oldfile newfile patchfile
.Op Ar old-extents new-extents
.Sh DESCRIPTION
.Nm
generates
.Ar newfile
from
.Ar oldfile
and
.Ar patchfile ,
where
.Ar patchfile
is a binary patch built by
.Xr bsdiff 1 .
.Pp
When provided,
.Ar old-extents
and
.Ar new-extents
instruct
.Nm
to read specific chunks of data from the old file and to write to specific
locations in the new file, respectively. Each is a comma-separated list of
extents of the form
.Ar offset : Ns Ar length ,
where
.Ar offset
is either -1 or a non-negative integer and
.Ar length
is a positive integer. An offset value of -1 denotes a sparse extent, namely a
sequence of zeros that entails neither reading nor writing of actual file
content.
.Pp
.Nm
uses memory equal to the size of 
.Ar newfile ,
but can tolerate a very small working set without a dramatic loss
of performance.
.Sh SEE ALSO
.Xr bsdiff 1
.Sh AUTHORS
.An Colin Percival Aq cperciva@freebsd.org