use strict;
use warnings;
use Test::More tests => 1;

my $in = <<EOIN;
# this is a new file
{
date 14/07/2016
time 11:15  
end 11:20   
total 30    
No  "FRUITS"

Fruit_Class
    {
    Name    "fruit 1"
    fruitName   "apple.fru"
    fruitId "0"         
    fruitCount  5
    fruitValue  6           
    }

    {
    Name    "fruit 2"
    fruitName   "orange.fru"
    fruitId "1"
    fruitCount  10
    fruitValue  20  
    }
}
EOIN

my $want = <<EOWANT;
# this is a new file
{date 14/07/2016
time 11:15  
end 11:20   
total 30    
No  FRUITS

Fruit_Class
    {
    Name    fruit_1
    fruitId 0           
    apple_fru.fruitCount    5
    fruitValue  6           
    }
Fruit_Class
    {
    Name    fruit_2
    fruitId 1
    orange_fru.fruitCount   10
    fruitValue  20  
    }
}
EOWANT

my $name = '';
my $out  = '';
my $nr   = 0;

for (split "\n", $in) {
    tr /"//d;
    s/ (\d)/_$1/ if $nr++ > 5;
    if (/^\s+fruitName\s+(.*?)$/) {
        ($name = $1) =~ s/\./_/;
        next;
    }
    s/fruitCount/$name.fruitCount/;
    s/^$/Fruit_Class/ if $nr > 10;
    if (/^{/) {
        $out .= $_;
        next;
    }
    $out .= "$_\n";
}

is ($out, $want);