http://www.perlmonks.org?node_id=142920


in reply to Ghost in the machine.

Could you explain how this is possible?

I've grepped through CPAN/*.pm, but I've failed to find any relevant code.

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Re: Re: Ghost in the machine.
by jmcnamara (Monsignor) on Feb 02, 2002 at 22:18 UTC

    This is more artifice than obfuscation.

    The "& _ x ord $ ;" code is used to convert my lowercase PerlMonks ID jmcnamara to my uppercase CPAN directory JMCNAMARA. I could have used uc but I thought that I should put in a little effort. ;-) 

        # The following are equivalent

    perl -MCPAN -e 'install jmcnamara & _ x ord $ ;'

    perl -MCPAN -e 'install "jmcnamara" & ( "_" x ord($;) )'

    perl -MCPAN -e 'install "jmcnamara" & ( "_" x 28 )'

    # With bitwise string "&" the longer string is truncated
    # to the length of the shorter string. Therefore:

    perl -MCPAN -e 'install "jmcnamara" & ( "_" x 9 )'

    perl -MCPAN -e 'install "jmcnamara" & "_________"'

    perl -MCPAN -e 'install JMCNAMARA'

    [download]

    Running this will cause CPAN to generate an error because you are trying to install a directory instead of module (or bundle). This helpfully translates my PerlMonks name into my real name. Here is the output as seen through tail -l.     Don't be silly, you can't install John McNamara ;-)

    This error message is buried in CPAN.pm.

    --
    John.

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