${hash}{"key"} is the same as $hash{"key"} (for reasonably named variables) so I'd suggest you adopt the second style for most uses. But in a string expansion, ${var} is used like $var but (at least usually) stops interpretting at the closing } (this is all a bit imprecise in an attempt to be DWIMish) so you can write "Sold $n ${item}s" instead of "Sold $n $item"."s". So "${hash}{'key'}" is the same as $hash."{'key'}".

And $hash{"key"} is the same as $hash{key} if "key" is just letters, numbers, and underscores. So you can use any of these:

    print "name is $input_queue{name}\n";
    print "name is $input_queue{'name'}\n";
    print qq<name is $input_queue{"name"}\n>;
    print "name is ".$input_queue{"name"}."\n";
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One minor correction:

And $hash{"key"} is the same as $hash{key} if "key" is just letters, numbers, and underscores.

I was worried that I didn't get that quite right and for good reason, too. $hash{"012"} is different than $hash{012} which is actually the same as $hash{"10"} since 012 (octal) == 10 (decimal). I worry there may be other special cases as well.

Also, on slightly old versions of Perl, things like $hash{time} will get you a warning because, on even older versions of Perl, that meant $hash{time()} and we needed a transition period before it could unambiguously mean $hash{"time"} like it does now.

        - tye (but my friends call me "Tye")

Here are several different ways to do what you're trying to do:

1. Use single quotes on the hash key.
   print "name is ${input_queue}{'name'}\n";
   
2. Don't use any quotes on the hash key.
   print "name is ${input_queue}{name}\n";
   This works because the key, 'name', is a bareword. It wouldn't work with a key like 'this-is-a-key'.
   
   
3. Use a quoting operator on the string.
   print qq(name is ${input_queue}{"name"}\n);
   qq{} is just like double-quotes, but you get to choose the delimiter.
   

UPDATE: Please see tye's answer for why ${input_queue}{'name'} doesn't mean the same as $input_queue{'name'} in a double-quoted string.

As a matter of habit I prefer to use single quotes when (I need quotes) just to emphasize that no interpolation is expected (though that should be kind of obvious in this case ;-). For me I think it makes reading the code later a bit easier than defaulting to double quotes everywhere.

print "name is ", $hash{$foo}{"name"}, "\n";
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my $thisname = $hash{$foo}{"name"};
print "name is $thisname\n";
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Thanks, folks. My programming habits had painted me into a corner.
I had hoped that there would be an embarrassingly simple answer, and there was!
Sankya, sankya, sankya.

print qq{name is $input_queue{"name"}};
# or
print qq{name is } . ${input_queue}{"name"};
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Cheers,
KM

2501 is right, hash keys are not considered to be barewords under -w and use strict, but you can also single quote it.

print "name: ${input_queue}{'name'}\n";
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Philosophy can be made out of anything. Or less -- Jerry A. Fodor

When I did that, I got the following:
name: {'name'}
as output.

Oops... In a double-quoted string, ${input_queue}{'name'} is interpreted as the scalar variable $input_queue, followed by the string {'name'}. I didn't realize that when I wrote my answer either.

So, you really do need to remove those extra braces: print "name: $input_queue{'name'}\n";