Generating files of varying variability?

Question

I have used /dev/zero and /dev/random to generate files of certain size. However, is there a way to control variability of generated files?

I would like to create few files that would have same uncompressed size, but different compressed size (compression ratio).

Only use /dev/random if you want to generate cryptagraphic keys as it may block when the entropy pool is exhausted. For normal operations like file generation use /dev/urandom. — Thomas Erker, Sep 6, 2015 at 19:10
@ThomasErker And if you want to generate cryptographic keys, use /dev/urandom as well. — Gilles 'SO- stop being evil', Sep 6, 2015 at 22:36

Thomas Erker · Accepted Answer · 2015-09-06 19:17:05Z

2

Quick and dirty:

cat /dev/urandom | tr -dc 'abcd' | dd count=10 bs=1 2>/dev/null

generates 10 bytes of (pseudo-)random sequence out of a, b, c, and d. Modify the alphabet (here "abcd") to get other compression rates.

answered Sep 6, 2015 at 19:17

Thomas Erker

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