I guess we can assume that the code you posted takes place inside a subroutine, otherwise the return would be pointless. Your subroutine returns a reference to a hash. So to print it, you'll need to dereference. Assume your subroutine is named mysub:

my $hash_ref = mysub();
while (my ($k, $v) = each(%$hash_ref)) {
    print "$k = $v\n";
}
[download]

...or...

my $hash_ref = mysub();
foreach my $key (keys %$hash_ref) {
    print "$k = $hash_ref->{$k}\n";
}
[download]

There are lots of other ways, but these are two that will work well for simple hashes. If your hash contains references to other entities, the solution will become more complicated. If all you want to do is just visualize the data structure, use Data::Dumper:

use Data::Dumper;

# ...

my $hash_ref = mysub();
print Dumper $hash_ref;
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Read below if you want to know how your post came to be nicely formatted:

Hi All 

I have a HASH built likr this

{
.
my @theta = $reg->theta();
$reg_coes{$id} = $theta[1];
$reg->print();
}        
    
return \%reg_coes;

what I want to do is print out the key and value in reg_coe, how do I 
+do that?
[download]

<p>Hi All </p>
<p>
I have a HASH built likr this
</p>
<c>
{
.
my @theta = $reg->theta();
$reg_coes{$id} = $theta[1];
$reg->print();
}        
    
return \%reg_coes;
</c>
<p>
what I want to do is print out the key and value in reg_coe, how do I 
+do that?
</p>
[download]