The following program reads in a file, and if it finds a line that starts with GRANT, followed by a line containing whatever, followed by two lines containing just a '/', it will remove the slashes from the latter two lines. This is how I interpret what you want; however, your specification isn't very exact.

    use strict;
    use warnings;

    my @buffer;
    for (1 .. 4) {
        push @buffer => scalar <>;
        last unless defined $buffer [-1];
    }

    while (defined $buffer [-1]) {
        if ($buffer [0] =~ /^GRANT/ && $buffer [2] eq "/\n"
                                    && $buffer [3] eq "/\n") {
            $buffer [2] = $buffer [3] = "\n";
        }
        print shift @buffer;
        push @buffer => scalar <>;
    }

    pop @buffer;
    print @buffer;

    __END__
[download]

Abigail