Hello Everyone, I am using the following code to search for the required pattern if in that document . 
seek(INPUT,$start_offset_target,0);
sysread(INPUT,$target_data,$end_offset_target-$start_offset_target+1 )
+;    
while ($target_data=~m/$pattern/gi)

                            {                    
                            
                            
                                $space='';
                                $c=0;
                                 $m = $1;                             
+                 
                                while($m=~/(\n)/gi)
                                {
                                 $c+=1;
                                }
                                $space=' ' x $c;
                                $space.=' ' x length($m);
                                $target_data=~s/$pattern/$space/i;
                            }

[download]
Cau plz suggest any further Improvement that can be done . P.S. The $target_data can contain 100000 bytes anf the required $pattern can be found many a times.

In reply to Replacing the pattern to search for by agynr

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