Shell Programming and Scripting

#!/usr/bin/perl 
#use strict; 
#use warnings; 
my $fh; 
my $log; 
my $line;
open($fh,"<","file1") or die "can not open file $fh : $!\n" ; 
open ($log,">","file2")or die "can not open file $log : $!\n" ; 
while($line = <$fh>)
{
   if ($line =~ /pattern1/ ) 
   {  
	  printf $log $line;
	  while($line = <$fh>) 
	  {
		 if($line =~ /pattern2/)
		 {
			printf $log $line;  
			last;
		 } else
		 {
			printf $log $line;  
		 }  
     }
     }
   } 
close $fh;
close $log;

#!/usr/bin/perl
use strict; # Its a good practice not to comment these two pragmas.
use warnings;

open I, "< file1";
open O, "> file2";

foreach (<I>) {
    if (/Pattern1/ .. /Pattern2/) { print O }
}

close O;
close I;

foreach (<I>) {
    if (/Pattern1/ .. /Pattern2/) { print O }
}