.TH XDELTA3 "1" "August 2009" "Xdelta3"
.SH NAME
xdelta3 \- VCDIFF (RFC 3284) binary diff tool
.SH SYNOPSIS
.B xdelta3 
.RI [ command ]
.RI [ options ] 
.RI [ input 
.RI [ output ]]
.SH DESCRIPTION
.B xdelta3
is a binary diff tool that uses the VCDIFF (RFC 3284) format and compression.
.SH COMMANDS
.TP
.BI config
prints xdelta3 configuration
.TP
.BI decode
decompress the input, also set by -d
.TP
.BI encode
compress the input, also set by -e (default)
.TP
.BI test
run the builtin tests
.TP
.BI printdelta
print information about the entire delta
.TP
.BI printhdr
print information about the first window
.TP
.BI printhdrs
print information about all windows
.TP
.BI recode
encode with new application/secondary settings

.SH OPTIONS
standard options:
.TP
.BI "\-0 .. \-9"
compression level
.TP
.BI "\-c"
use stdout
.TP
.BI "\-d"
decompress
.TP
.BI \-e
compress
.TP
.BI \-f
force overwrite
.TP
.BI \-h
show help
.TP
.BI \-q
be quiet
.TP
.BI \-v
be verbose (max 2)
.TP
.BI \-V
show version

.TP
memory options:
.TP
.BI \-B 
.RI bytes
source window size
.TP
.BI \-W 
.RI bytes
input window size
.TP
.BI \-P 
.RI size
compression duplicates window
.TP
.BI \-I 
.RI size
instruction buffer size (0 = unlimited)

.TP
compression options:
.TP
.BI \-s
.RI source
source file to copy from (if any)
.TP
.BI "\-S " [djw|fgk]
enable/disable secondary compression
.TP
.BI \-N
disable small string-matching compression
.TP
.BI \-D
disable external decompression (encode/decode)
.TP
.BI \-R
disable external recompression (decode)
.TP
.BI \-n
disable checksum (encode/decode)
.TP
.BI \-C 
soft config (encode, undocumented)
.TP
.BI "\-A " [apphead]
disable/provide application header (encode)
.TP
.BI \-J
disable output (check/compute only)
.TP
.BI \-T
use alternate code table (test)

.SH NOTES
The 
.B XDELTA
environment variable may contain extra args:

.RS
XDELTA="-s source-x.y.tar.gz" \\
.br
tar --use-compress-program=xdelta3 -cf \\
.br
target-x.z.tar.gz.vcdiff target-x.y/

.SH EXAMPLES

Compress the differences between SOURCE and TARGET, yielding OUT, 
using "djw" secondary compression:

xdelta3 -S djw -s SOURCE TARGET OUT

Do the same, using standard input and output:

xdelta3 -S djw -s SOURCE < TARGET > OUT

To decompress OUT, using SOURCE, yielding TARGET:

xdelta3 -d -s SOURCE OUT TARGET

.SH AUTHOR
xdelta3 was written by Josh MacDonald <josh.macdonald@gmail.com>.
.PP
This manual page was written by Leo 'costela' Antunes <costela@debian.org>
for the Debian project (but may be used by others).