#!/usr/bin/perl

use strict;
use warnings;

while(<DATA>){
    chomp();
    print "before: $_\n";
    s/(\d+\s+)(.+)/$1 (Birthday) $2 - singer/;
    print "after: $_\n";
  }

__DATA__
January 1, 1915      Franck Pourcel
January 3, 1926     George Martin
January 3, 1945     Stephen Stills
January 3, 1946     John Paul Jones
January 4, 1942     John McLaughlin
January 5, 1950     Chris Stein