You could just as easily do it with an array or list then. Modify the code hippo gave to use an array instead:
#!/usr/bin/env perl
use strict;
use warnings;
my @names = (
'BULLOCK JOE A',
'SMITH, A DOE',
);
for my $fullname (@names) {
my ($sname, $fname) = $fullname =~ /([A-Z]{3,})/g;
print "Forename $fname extracted from $fullname";
}
There are three assumptions that need to be met: both first and last names must be at least three letters long, the last name must come first, and the middle name must be an initial (or at least less than three letters long. If you cannot meet those conditions, you will have a hard problem.