I don't see how that would work. You're proposing fixing a performance issue caused by fork/exec/re-reading a large file from the beginning on each iteration, by doing exactly the same thing but with a virtual machine added in the middle instead of optimised C code? This isn't a perl-specific question you're asking, it's fairly generic. The proposed solutions (e.g., Tie::File) include some perl-specific suggestions, and some that aren't (read the file into memory as a list/array - you can do that in C++ with the STL fairly easily, and Java should make it pretty simple, too), but the general issue is language-agnostic.

Instead, if you read it all into memory, you can use likely just a line to duplicate. Without testing or even compiling:

# do this once.  OUTSIDE OF YOUR LOOP.
my @read_source_lines = do {
  open my $fh, '<', $read_source or die "Can't read from $read_source:
+ $!";
  <$fh>
};
# you may also need:
chomp @read_source_lines; # gets rid of \n's.

# inside the loop, instead of $strx/$str5:
my $str5 = $read_source_lines[$recnum];
print REPORT "$_|$recnum$str5\n";
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Thank you so much for your genuine help and time! Appreciate much! This piece of code you have suggested( without using Tie::File) , works perfectly fine. now the whole processing takes only a second. I have heard always perl is very fast, now saw its performance. thanks again for making me a PERL fan too :-)