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资源说明：Parallel, indexed xz compressor
pixz
====
[](https://travis-ci.org/vasi/pixz)
Pixz (pronounced *pixie*) is a parallel, indexing version of `xz`.
Repository: https://github.com/vasi/pixz
Downloads: https://github.com/vasi/pixz/releases
pixz vs xz
----------
The existing [XZ Utils](http://tukaani.org/xz/) provide great compression in the `.xz` file format,
but they produce just one big block of compressed data. Pixz instead produces a collection of
smaller blocks which makes random access to the original data possible. This is especially useful
for large tarballs.
### Differences to xz
- `pixz` automatically indexes tarballs during compression
- `pixz` supports parallel decompression, which `xz` does not
- `pixz` defaults to using all available CPU cores, while `xz` defaults to using only one core
- `pixz` provides `-i` and `-o` command line options to specify input and output file
- `pixz` does not support the command line option `-z` or `--compress`
- `pixz` does not support the command line option `-c` or `--stdout`
- `-f` command line option is incompatible
- `-l` command line option output differs
- `-q` command line option is incompatible
- `-t` command line option is incompatible
Building pixz
-------------
General help about the building process's configuration step can be acquired via:
```
./configure --help
```
### Dependencies
- pthreads
- liblzma 4.999.9-beta-212 or later (from the xz distribution)
- libarchive 2.8 or later
- AsciiDoc to generate the man page
### Build from Release Tarball
```
./configure
make
make install
```
You many need `sudo` permissions to run `make install`.
### Build from GitHub
```
git clone https://github.com/vasi/pixz.git
cd pixz
./autogen.sh
./configure
make
make install
```
You many need `sudo` permissions to run `make install`.
Usage
-----
### Single Files
Compress a single file (no tarball, just compression), multi-core:
pixz bar bar.xz
Decompress it, multi-core:
pixz -d bar.xz bar
### Tarballs
Compress and index a tarball, multi-core:
pixz foo.tar foo.tpxz
Very quickly list the contents of the compressed tarball:
pixz -l foo.tpxz
Decompress the tarball, multi-core:
pixz -d foo.tpxz foo.tar
Very quickly extract a single file, multi-core, also verifies that contents match index:
pixz -x dir/file < foo.tpxz | tar x
Create a tarball using pixz for multi-core compression:
tar -Ipixz -cf foo.tpxz foo/
### Specifying Input and Output
These are the same (also work for `-x`, `-d` and `-l` as well):
pixz foo.tar foo.tpxz
pixz < foo.tar > foo.tpxz
pixz -i foo.tar -o foo.tpxz
Extract the files from `foo.tpxz` into `foo.tar`:
pixz -x -i foo.tpxz -o foo.tar file1 file2 ...
Compress to `foo.tpxz`, removing the original:
pixz foo.tar
Extract to `foo.tar`, removing the original:
pixz -d foo.tpxz
### Other Flags
Faster, worse compression:
pixz -1 foo.tar
Better, slower compression:
pixz -9 foo.tar
Use exactly 2 threads:
pixz -p 2 foo.tar
Compress, but do not treat it as a tarball, i.e. do not index it:
pixz -t foo.tar
Decompress, but do not check that contents match index:
pixz -d -t foo.tpxz
List the xz blocks instead of files:
pixz -l -t foo.tpxz
For even more tuning flags, check the manual page:
man pixz
Comparison to other Tools
-------------------------
### plzip
- about equally complex and efficient
- lzip format seems less-used
- version 1 is theoretically indexable, I think
### ChopZip
- written in Python, much simpler
- more flexible, supports arbitrary compression programs
- uses streams instead of blocks, not indexable
- splits input and then combines output, much higher disk usage
### pxz
- simpler code
- uses OpenMP instead of pthreads
- uses streams instead of blocks, not indexable
- uses temporary files and does not combine them until the whole file is compressed, high disk and
memory usage
### pbzip2
- not indexable
- appears slow
- bzip2 algorithm is non-ideal
### pigz
- not indexable
### dictzip, idzip
- not parallel
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