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Compress log files efficiently with 7zip

 7-zip is a popular compression tool and  famous for high compression ratio.

But unfortunately, there is no description in the man pages about switching the compression algorithm to PPMd . Actually, PPMd provides very high compression ratio with lower CPU power consumption with a text data, and I would like to show its efficiency.

Here is an example. Below is a comparison of size and CPU time between variety of  compression methods .

   command       size      time   
7z a -tzip -mx=9    3699 bytes   0m0.410s
7z a -tgzip -mx=9    3610 bytes   0m0.411s
7z a -tbzip2 -mx=9    3363 bytes    0m0.608s
7z a -m0=lzma -mx=9    3406  bytes   0m0.109s
7z a -m0=PPMd -mx=9    2699 bytes   0m0.058s

The original file is a 6795 byte text file. As you can see, efficiency of PPMd is outstanding!

PPMd helps me a lot to compact log files.
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