Do this if what only what you require is the bit between:

print grep { !/process/  } <>;
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perl <script>.pl <input>.txt
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prints

ksjhfk
kfh
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You could also put this in an array

my @process = grep { !/process/  } <>;
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However this would just be each element for each line. If you wanted them grouped you need something more complex using assertions ( if you do it the inefficent way like i have )
John,

UPDATE: This would group them

{
    local undef $/;
    print split /process \s \w+ (.+?) end \s process/xms, <>;
}
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P.S. Don't actually use these methods of doing it, There just other ways to do it.