$ cat example.pl 
my $string = 'some value';  # these
my $int = 12; # are
my $float = 1.2; # scalars
$ perltidy -b example.pl 
$ cat example.pl
my $string = 'some value';    # these
my $int    = 12;              # are
my $float  = 1.2;             # scalars