From 099d844292f60f9d58914da29e5773204dc55e7a Mon Sep 17 00:00:00 2001 From: Julian Seward Date: Sun, 30 Dec 2001 22:13:13 +0100 Subject: bzip2-1.0.2 --- bzip2.1 | 56 +++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 35 insertions(+), 21 deletions(-) (limited to 'bzip2.1') diff --git a/bzip2.1 b/bzip2.1 index 7de54a0..623435c 100644 --- a/bzip2.1 +++ b/bzip2.1 @@ -1,7 +1,7 @@ .PU .TH bzip2 1 .SH NAME -bzip2, bunzip2 \- a block-sorting file compressor, v1.0 +bzip2, bunzip2 \- a block-sorting file compressor, v1.0.2 .br bzcat \- decompresses files to stdout .br @@ -197,7 +197,7 @@ to decompress. .TP .B \-z --compress The complement to \-d: forces compression, regardless of the -invokation name. +invocation name. .TP .B \-t --test Check integrity of the specified file(s), but don't decompress them. @@ -211,6 +211,10 @@ existing output files. Also forces .I bzip2 to break hard links to files, which it otherwise wouldn't do. + +bzip2 normally declines to decompress files which don't have the +correct magic header bytes. If forced (-f), however, it will pass +such files through unmodified. This is how GNU gzip behaves. .TP .B \-k --keep Keep (don't delete) input files during compression @@ -239,9 +243,13 @@ information which is primarily of interest for diagnostic purposes. .B \-L --license -V --version Display the software version, license terms and conditions. .TP -.B \-1 to \-9 +.B \-1 (or \-\-fast) to \-9 (or \-\-best) Set the block size to 100 k, 200 k .. 900 k when compressing. Has no effect when decompressing. See MEMORY MANAGEMENT below. +The \-\-fast and \-\-best aliases are primarily for GNU gzip +compatibility. In particular, \-\-fast doesn't make things +significantly faster. +And \-\-best merely selects the default behaviour. .TP .B \-- Treats all subsequent arguments as file names, even if they start @@ -352,11 +360,11 @@ undamaged. .I bzip2recover takes a single argument, the name of the damaged file, -and writes a number of files "rec0001file.bz2", -"rec0002file.bz2", etc, containing the extracted blocks. +and writes a number of files "rec00001file.bz2", +"rec00002file.bz2", etc, containing the extracted blocks. The output filenames are designed so that the use of wildcards in subsequent processing -- for example, -"bzip2 -dc rec*file.bz2 > recovered_data" -- lists the files in +"bzip2 -dc rec*file.bz2 > recovered_data" -- processes the files in the correct order. .I bzip2recover @@ -397,27 +405,31 @@ I/O error messages are not as helpful as they could be. tries hard to detect I/O errors and exit cleanly, but the details of what the problem is sometimes seem rather misleading. -This manual page pertains to version 1.0 of +This manual page pertains to version 1.0.2 of .I bzip2. -Compressed -data created by this version is entirely forwards and backwards -compatible with the previous public releases, versions 0.1pl2, 0.9.0 -and 0.9.5, -but with the following exception: 0.9.0 and above can correctly -decompress multiple concatenated compressed files. 0.1pl2 cannot do -this; it will stop after decompressing just the first file in the -stream. +Compressed data created by this version is entirely forwards and +backwards compatible with the previous public releases, versions +0.1pl2, 0.9.0, 0.9.5, 1.0.0 and 1.0.1, but with the following +exception: 0.9.0 and above can correctly decompress multiple +concatenated compressed files. 0.1pl2 cannot do this; it will stop +after decompressing just the first file in the stream. .I bzip2recover -uses 32-bit integers to represent bit positions in -compressed files, so it cannot handle compressed files more than 512 -megabytes long. This could easily be fixed. +versions prior to this one, 1.0.2, used 32-bit integers to represent +bit positions in compressed files, so it could not handle compressed +files more than 512 megabytes long. Version 1.0.2 and above uses +64-bit ints on some platforms which support them (GNU supported +targets, and Windows). To establish whether or not bzip2recover was +built with such a limitation, run it without arguments. In any event +you can build yourself an unlimited version if you can recompile it +with MaybeUInt64 set to be an unsigned 64-bit integer. + + .SH AUTHOR Julian Seward, jseward@acm.org. -http://sourceware.cygnus.com/bzip2 -http://www.muraroa.demon.co.uk +http://sources.redhat.com/bzip2 The ideas embodied in .I bzip2 @@ -434,6 +446,8 @@ indebted for their help, support and advice. See the manual in the source distribution for pointers to sources of documentation. Christian von Roques encouraged me to look for faster sorting algorithms, so as to speed up compression. Bela Lubkin encouraged me to improve the -worst-case compression performance. Many people sent patches, helped +worst-case compression performance. +The bz* scripts are derived from those of GNU gzip. +Many people sent patches, helped with portability problems, lent machines, gave advice and were generally helpful. -- cgit v1.2.3-55-g6feb