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File bzme.1 of Package bzip2

.PU
.TH bzip2 1
.SH NAME
bzme \- recompress gziped, ziped, ... files into bzip2

.SH SYNOPSIS
.ll +8
.B bzmz
.RB [ " \-fh " ]
[
.I "filenames \&..."
]

.SH DESCRIPTION
.I bzme
recompresses files using the Burrows-Wheeler block sorting text compression
algorithm, and Huffman coding.  Compression is generally considerably better
than that achieved by more conventional LZ77/LZ78-based compressors,
and approaches the performance of the PPM family of statistical compressors.

.I bzme
expects a list of file names to accompany the command-line flags.
Each file is replaced by a recompressed version of itself, with the name
as described in 
.B "NEW NAMES"
section.

.I bzme
won't overwrite by default existing files.  If you want this to happen, specify
the \-f flag.

.SH "NEW NAMES"
.I bzip2
attempts to guess the filename for the decompressed file 
from that of the compressed file as follows:

filename.tgz    becomes   filename.tar.bz2
       filename.tar.gz becomes   filename.tar.bz2
       filename.zip    becomes   filename.tar.bz2
       filename.z      becomes   filename.bz2
       filename.Z      becomes   filename.bz2
       filename.gz     becomes   filename.bz2

If the file does not end in one of the recognised endings, \fI.tgz\fP,

or \fI.zip\fP,
.I bzme 
complains that it cannot guess if the name of the recompressed file (ie it
doesn't detect the original name to be a file compressed in a known format)

.SH OPTIONS
.TP
.B \-f
Force overwrite of output files, even if
.I -k
is used.  Normally,
.I bzip2 
will not overwrite existing output files.

.TP
.B \-k
Keep (don't delete) input files during compression
or decompression.
.".TP
.".B \-q --quiet
."Suppress non-essential warning messages.  Messages pertaining to
."I/O errors and other critical events will not be suppressed.
.".TP
.".B \-v --verbose
."Verbose mode -- dysplay space gain (default)
.".TP
.".B \-L --license -V --version
."Display the software version, license terms and conditions.

.SH SECURITY
.I bzme
will keep source file if there's an error while decompressing source file
or recompressing new file (or
.I -k
option is used of course).

.I bzme
won't overwite the target file, even if
.I -k
option is used, if the source file doesn't exists.

As a self-check for your protection, 
.I bzip2
uses 32-bit CRCs to make sure that the decompressed version of a file is
identical to the original.
.BR
This offers a better protection against corruption
of the compressed data than offered by gzip.

.SH SPACE GAIN
Compression is only performed if the compressed file is smaller than the
original: the original file is only removed if the newly compressed file
is smaller, else the new recompressed file is deleted.

Text (aka non binary) files're quite nearly always better compressed
by bzip2 rather than gzip.

.SH MEMORY VS SPACE TRADEOFF
There're two things :
.TP
.B Consumed CPU time
The needed cpu time is reduced by decompressing only one time.
Files to recompress were compressed through compress or gzip, used to be
decompressed by gunzip -t in order to check that the original file was ok.
This resulted in passing two times the data in the decompression process
(one to check integrity, one to recompress).
temporary space usage will be zero since bzme will use a pipe
rather than a temporary file as it does in the early ages.
Source error're detected through bash PIPESTATUS feature.
.TP
.B Occupied space
While recompressing files, if they were compressed through compress or gzip,
temporary space usage will be zero since bzme will use a pipe
rather than a temporary file as it did in the early ages.
Source error're detected through bash PIPESTATUS feature.
Zip files're still fully decompressed on disk.

As for the recompressed file and original file, only the smallest file
is kept.

.SH RETURN VALUES
0 for a normal exit.
1 will be returned if an unknown option is passed.

.SH BUGS
Bash getopt (which is used to analyse options) isn't gnu style aware, ie cmd
opt1 file1 file2 opt2 will result in ignoring opt2 option.

Solaris/SunOs du doesn't supports gnu option, and thus, bzme won't
work on those OSes unless GNU fileutils got installed.
.BR
I had once a day patched bzme to use right options for solaris but i had
lost my changes.
.LP
So solaris remains unsupported.

.SH "SEE ALSO"
bzip2(1), bunzip2(1)

.SH AUTHOR
Thierry Vignaud <tvignaud@mandrakesoft.com>, 1999-2002

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