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1 .TH pbzip2 1
2 .SH NAME
3 pbzip2 \- parallel bzip2 file compressor, v1.1.10
4 .SH SYNOPSIS
5 .B pbzip2
6 .RB [ " \-123456789 " ]
7 .RB [ " \-b#cdfhklm#p#qrS#tvVz " ]
8 [
9 .I "filenames \&..."
10 ]
11 .SH DESCRIPTION
12 .I pbzip2
13 is a parallel implementation of the bzip2 block-sorting file
14 compressor that uses pthreads and achieves near-linear speedup on SMP
15 machines. The output of this version is fully compatible with bzip2
16 v1.0.2 or newer (ie: anything compressed with
17 .I pbzip2
18 can be decompressed with bzip2).
19 .PP
20 .I pbzip2
21 should work on any system that has a pthreads compatible C++
22 compiler (such as gcc). It has been tested on: Linux, Windows (cygwin),
23 Solaris, Tru64/OSF1, HP-UX, and Irix.
24 .PP
25 The default settings for
26 .I pbzip2
27 will work well in most cases. The only switch you will likely need to
28 use is -d to decompress files and -p to set the # of processors for
29 .I pbzip2
30 to use if autodetect is not supported
31 on your system, or you want to use a specific # of CPUs.
32 .SH OPTIONS
33 .TP
34 .B \-b#
35 Where # is block size in 100k steps (default 9 = 900k)
36 .TP
37 .B \-c, \-\-stdout
38 Output to standard out (stdout)
39 .TP
40 .B \-d,\-\-decompress
41 Decompress file
42 .TP
43 .B \-f,\-\-force
44 Force, overwrite existing output file
45 .TP
46 .B \-h,\-\-help
47 Print this help message
48 .TP
49 .B \-k,\-\-keep
50 Keep input file, do not delete
51 .TP
52 .B \-l,\-\-loadavg
53 Load average determines max number processors to use
54 .TP
55 .B \-m#
56 Where # is max memory usage in 1MB steps (default 100 = 100MB)
57 .TP
58 .B \-p#
59 Where # is the number of processors (default: autodetect)
60 .TP
61 .B \-q,\-\-quiet
62 Quiet mode (default)
63 .TP
64 .B \-r,\-\-read
65 Read entire input file into RAM and split between processors
66 .TP
67 .B \-S#
68 Child thread stack size in 1KB steps (default stack size if unspecified)
69 .TP
70 .B \-t,\-\-test
71 Test compressed file integrity
72 .TP
73 .B \-v,\-\-verbose
74 Verbose mode
75 .TP
76 .B \-V
77 Display version info for
78 .I pbzip2
79 then exit
80 .TP
81 .B \-z,\-\-compress
82 Compress file (default)
83 .TP
84 .B \-1,\-\-fast ... \-9,\-\-best
85 Set BWT block size to 100k .. 900k (default 900k).
86 .TP
87 .B \-\-ignore-trailing-garbage=#
88 Ignore trailing garbage flag (1 - ignored; 0 - forbidden)
89 .PP
90 If no file names are given, pbzip2 compresses or decompresses from standard input to standard output.
91 .SH FILE SIZES
92 You should be able to compress files larger than 4GB with
93 .I pbzip2.
94 .PP
95 Files that are compressed with
96 .I pbzip2
97 are broken up into pieces and
98 each individual piece is compressed. This is how
99 .I pbzip2
100 runs faster
101 on multiple CPUs since the pieces can be compressed simultaneously.
102 The final .bz2 file may be slightly larger than if it was compressed
103 with the regular bzip2 program due to this file splitting (usually
104 less than 0.2% larger). Files that are compressed with
105 .I pbzip2
106 will also gain considerable speedup when decompressed using
107 .I pbzip2.
108 .PP
109 Files that were compressed using bzip2 will not see speedup since
110 bzip2 packages the data into a single chunk that cannot be split
111 between processors.
112 .SH EXAMPLES
113 Example 1: pbzip2 myfile.tar
114 .PP
115 This example will compress the file "myfile.tar" into the compressed file
116 "myfile.tar.bz2". It will use the autodetected # of processors (or 2
117 processors if autodetect not supported) with the default file block size
118 of 900k and default BWT block size of 900k.
119 .PP
120 Example 2: pbzip2 -b15k myfile.tar
121 .PP
122 This example will compress the file "myfile.tar" into the compressed file
123 "myfile.tar.bz2". It will use the autodetected # of processors (or 2
124 processors if autodetect not supported) with a file block size of 1500k
125 and a BWT block size of 900k. The file "myfile.tar" will not be deleted
126 after compression is finished.
127 .PP
128 Example 3: pbzip2 -p4 -r -5 myfile.tar second*.txt
129 .PP
130 This example will compress the file "myfile.tar" into the compressed file
131 "myfile.tar.bz2". It will use 4 processors with a BWT block size of 500k.
132 The file block size will be the size of "myfile.tar" divided by 4 (# of
133 processors) so that the data will be split evenly among each processor.
134 This requires you have enough RAM for pbzip2 to read the entire file into
135 memory for compression. Pbzip2 will then use the same options to compress
136 all other files that match the wildcard "second*.txt" in that directory.
137 .PP
138 Example 4: tar cf myfile.tar.bz2 --use-compress-prog=pbzip2 dir_to_compress/
139 .br
140 Example 4: tar -c directory_to_compress/ | pbzip2 -c > myfile.tar.bz2
141 .PP
142 These examples will compress the data being given to pbzip2 via pipe
143 from TAR into the compressed file "myfile.tar.bz2". It will use the
144 autodetected # of processors (or 2 processors if autodetect not
145 supported) with the default file block size of 900k and default BWT
146 block size of 900k. TAR is collecting all of the files from the
147 "directory_to_compress/" directory and passing the data to pbzip2 as
148 it works.
149 .PP
150 Example 5: pbzip2 -d -m500 myfile.tar.bz2
151 .PP
152 This example will decompress the file "myfile.tar.bz2" into the decompressed
153 file "myfile.tar". It will use the autodetected # of processors (or 2
154 processors if autodetect not supported). It will use a maximum of 500MB of
155 memory for decompression. The switches -b, -r, and -1..-9 are not valid for
156 decompression.
157 .PP
158 Example 6: pbzip2 -dc myfile.tar.bz2 | tar x
159 .PP
160 This example will decompress and untar the file "myfile.tar.bz2" piping
161 the output of the decompressing pbzip2 to tar.
162 .PP
163 Example 7: pbzip2 -c < myfile.txt > myfile.txt.bz2
164 .PP
165 This example will read myfile.txt from standard input compressing
166 it to standard output which is redirected to to myfile.txt.bz2.
167 .SH "SEE ALSO"
168 bzip2(1)
169 gzip(1)
170 lzip(1)
171 rzip(1)
172 zip(1)
173 .SH AUTHOR
174 Jeff Gilchrist
175
176 http://compression.ca