use warnings;
 use strict;
 
 open my $fh, '+>', 'output.txt'
   or die("Can't open the damn file!: $!");
 open FILE, 'c:/aperlphone/myphonelist.txt' or die $!;   
  
while(my $line == 'FILE')     # semi-colon removed(run1) & (run2)equity test to '=='
     {                              # extra empty line removed: HazNav (not an error)
     chomp $line;
     my ($name, $num) = split(/\s+(?=\d)/, $line);  # missing semi-colon inserted (run 1)
 
     # some lines have whitespace after the num
 
     $num =~ s/\s+//g;
 
     if ($num =~ /^\d{4}$/){
         $num = "(333)-447-$num";
     }
     elsif ($num =~ /^\d{3}-\d{4}$/){
         $num = "(333)-$num";
     }
 
     print $fh "$name $num\n";
 }