Another varation:

$cd .= $_ while <STDIN>;

sub jump_ahead {
        (($ch_ptr = index($cd, ']', $ch_ptr))) if (!$cell[$cl_ptr]);
}

sub jump_behind {
        (($ch_ptr = rindex($cd, '[', $ch_ptr))) if ($cell[$cl_ptr]);
}

while (1) {
        exit if ($ch_ptr == length($cd));
        $ch = substr($cd, $ch_ptr++, 1);

        ($ch eq '>') && $cl_ptr++;
        ($ch eq '<') && $cl_ptr--;
        ($ch eq '+') && $cell[$cl_ptr]++;
        ($ch eq '-') && $cell[$cl_ptr]--;
        ($ch eq '.') && (($_ = chr($cell[$cl_ptr])) && print);
        ($ch eq ',') && ($cell[$cl_ptr] = ord(getc));
        ($ch eq '[') && jump_head;
        ($ch eq ']') && jump_behind;
}
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Although I prefer your version :)