my ($File_1_line,$File_2_line);
open(F1,"File_1");
open(F2,"File_2");

while($File_1_line=<F1>)
{
    #chomp $File_1_line;
    my @data=split(' ',$File_1_line);

    seek(F2,0,0);
    while($File_2_line=<F2>)
    {
      chomp $File_2_line;
      print "@data\n" if($data[0] eq $File_2_line);
    }


}