#Input file:

#SomeChar
#	START
#value
#	END
#AnotherChar


#This code extract START .. END (OK)
while (<>) {

my $stag='START';
my $etag='END';
my $line;
$line=$_;
  if ($line=~/$stag/../$etag/)
  {
   print $line;
  }
}

#This code extract START .. END + everything after (NOT GOOD)


sub getInfoFromMultipleLine
{
    #Openning file for reading
    open(IFH,"$InputFile") || die "Can't open file: $InputFile\n";
    my $stag='START';
    my $etag='END';
    my $line;
      while($line=<IFH>)
      {
        if ($line=~m/$stag/../$etag/)
        {
          print $line;
        }
      }
}
$InputFile="$LocationOfTheScriptsDirectory\\A.txt";
getInfoFromMultipleLine();