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Hello, |
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|
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On Fri, 31 Oct 2014, Rich Freeman wrote: |
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>On Fri, Oct 31, 2014 at 11:59 AM, <meino.cramer@×××.de> wrote: |
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>> I am currently checking the compression tools I know of for the |
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>> best compression ration. But I will definitly miss those I dont |
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>> know... |
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>> And sometimes one can do magic with option and switches of that |
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>> kind of tools I also dont know of. |
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|
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With 100k pseudo-random digits from bash's $RANDOM % 10 and a |
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linebreak every 100 digits (in t.lst) I get this (each with --best / |
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-9 / -m5 (rar) compression-level option): |
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|
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$ du -b * | sort -rn |
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101000 t.lst |
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61544 t.lzop |
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50733 t.zoo |
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49696 t.zip |
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49609 t.lha |
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49554 t.gz |
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48907 t.Z |
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44942 t.rar |
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44661 t.rzip |
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44638 t.7z |
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44592 t.xz |
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44572 t.bz2 |
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44546 t.lzma |
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44543 t.lzip |
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|
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What I find remarkable is that both gzip and good old compress (.Z) |
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are rather good ;) And above is probably a quite comprehensible list, |
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and except .Z, .gz and .bz2 all are name as the binaries used to |
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create them. |
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|
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I'd use bzip2/xz/lz as there are e.g. [blx]z(e)(grep|cat|less), but |
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not e.g. 7zgrep, and I guess they can easy access to those archives |
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quite a bit. |
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|
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>I can't imagine that any tool will do much better than something like |
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>lzo, gzip, xz, etc. You'll definitely benefit from compression though |
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>- your text files full of digits are encoding 3.3 bits of information |
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>in an 8-bit ascii character and even if the order of digits in pi can |
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>be treated as purely random just about any compression algorithm is |
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>going to get pretty close to that 3.3 bits per digit figure. |
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|
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Good estimate: |
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|
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$ calc '101000/(8/3.3)' |
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41662.5 |
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and I get from (lzip) |
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$ calc 44543*8/101000 |
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3.528... (bits/digit) |
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to zip: |
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$ calc 49696*8/101000 |
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~3.93 (bits/digit) |
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|
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HTH, |
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-dnh |
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|
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-- |
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Q: Hobbies? |
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A: Hating music. -- Marvin |
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