use strict;
use warnings;

while ( <DATA> ) {
  my @fields = split /,/;
  while ( my @chunk = splice @fields, 0, 3 ) {
    printf "%-17s", $_ for @chunk;
	print "\n";
  }
}

__DATA__
1,fred,jones,555-1212,123 Main St.,Boston,MA,00001,test@test.com
2,mary,smith,222-1515,321 Least St.,Hanover,NH,02022,testmary@test.com
3,jack,least,122-5511,231 Last St.,Franklin,CT,06001,nomail@test.com