Sorry, I didn't see you asking that question. Variables are interpolated in double-quoted strings but not single-quoted, that's all. If your entire string is the value of some variable, you don't need the quotes at all, as exor674 pointed out.
But anyway. Please don't take 500 errors (or technical advice) personally, if at all possible. It will happen to everyone, even those who know perl. You'll hit an error, you'll need a second opinion. That's normal. I think the best thing you can do is know where to look to start troubleshooting. I assume you need that advice only because you came to this discussion without the error message in hand. It also matters what this thread will look like to others who want to learn -- I just didn't want to leave your question unanswered, even though it didn't entirely make sense to me. Sorry if that was too vague.
That said, I stand by my first reactions here: (a) the variable is going to be undef at that point in the code, (b) it doesn't matter which file you edit as long as both of them have your changes when you're done, and (c) please look in error_log for more diagnostic info when you get an error. My intuition tells me that using an undefined variable could have been the error, but I can't say exactly what happened without seeing the error message.
no subject
But anyway. Please don't take 500 errors (or technical advice) personally, if at all possible. It will happen to everyone, even those who know perl. You'll hit an error, you'll need a second opinion. That's normal. I think the best thing you can do is know where to look to start troubleshooting. I assume you need that advice only because you came to this discussion without the error message in hand. It also matters what this thread will look like to others who want to learn -- I just didn't want to leave your question unanswered, even though it didn't entirely make sense to me. Sorry if that was too vague.
That said, I stand by my first reactions here: (a) the variable is going to be undef at that point in the code, (b) it doesn't matter which file you edit as long as both of them have your changes when you're done, and (c) please look in error_log for more diagnostic info when you get an error. My intuition tells me that using an undefined variable could have been the error, but I can't say exactly what happened without seeing the error message.