#!usr/local/bin/perl

$filename = "input.txt";
open (FILE,"<$filename");
@fileinput=<FILE>;
close(FILE);

foreach $line(@fileinput)
{
# Capitalieze first letter of each word found after marker AU: and add written by:
     $line=~s/AU:\s\b(\w+)\s\b(\w+)|AU:\s\b(\w+.)|AU: ([\s\w\s\b]+)/AU: Written by: \u$1 \u$2\u$3/g;
     

     #extract numeric id in ()
     if($line=~/\(\d{6}\)/)
     {$line=~s/$&//;
      print "$&\n";
     }