Thanks for your commnets. I'll try to improve my coding skills. Please find my actual code below. 
#!/usr/bin/perl
use strict;
use warnings;

our $fh;
our $log;

open($fh,">","block.power");
open ($log,">","temp.log") or die "can not open file $log : $!\n" ;
while($fh){
   if (/Total Design Power Summary \(Worst/ .. /\|Total/)  {
      printf $log;
   }
}

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In reply to Re^4: Extract lines between two patterns by mnithink
in thread Extract lines between two patterns by mnithink

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