The m modifier is useless since ^, $, etc isn't used. In fact, why aren't you using \z when you change the IRS? And why not use "\n\n=" as the IRS? 
local $/ = "\n\n=";
while (<DATA>) {
    s/\n\n=\z/\n=/;
    print;
}

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In reply to Re^2: Why does my Perl regex substitution for linebreak fail? by ikegami
in thread Why does my Perl regex substitution for linebreak fail? by pat_mc

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