Re: OT: Base64 encoding in obfuscated Perl (was: Re: How to prevent the '<hostname> Daily Mail Report for <date>' message getting caught by body_checks.)

From: Liviu Daia (no email)
Date: Mon Sep 01 2003 - 15:06:51 EDT


On 31 August 2003, Liviu Daia <> wrote:
> Off topic, but still related: can some Perl-Fu master out there
> please explain (preferably in layman terms) why the following
> abomination works fine for encoding files as Base64:
>
> perl -MMIME::Base64 -e 'print encode_base64 $b while (read STDIN, $b, 57)' <file
>
> while this one only works for small files:
>
> perl -MMIME::Base64 -pne '$/=\57; $_=encode_base64 $_' <file

    FWIW: the second incantation doesn't work because $/ is changed in
the middle of the loop, after the first chunk has been read. Thanks to
Kyle Dent for helping me out of it.

    Conclusion: the following can be used as a poor man's Base64
encoder:

perl -MMIME::Base64 -pe 'BEGIN{$/=\57};$_=encode_base64 $_' <file

    Regards,

    Liviu Daia

-- 
Dr. Liviu Daia               e-mail:   
Institute of Mathematics     web page: http://www.imar.ro/~daia
of the Romanian Academy      PGP key:  http://www.imar.ro/~daia/daia.asc







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