I assume you're not advocating for magic numbers - I might have said that a constant that isn't modifiable from outside the module is a problem.

I agree. I meant "don't use constants, make it variables that can be changed from the outside".

That said, i'm a lazy bum and i use some magic numbers in code i write.

• I almost always use the magic numbers 1 and 0 for true and false. I'm just assuming that anyone reading perl code knows what that means.
• When writing web stuff, i use just the HTTP status codes instead of their names. So i'd write 404 instead of instead of something like $HTTP_STATUS_CODES{'Not Found'}. Force of habit, i guess, because in my brain they're exactly the same thing.
• When doing basic computer maths like bitshifting, i'm just assuming anyone reading the code understands that $x >> 8 means "shift by one byte to the right".
• Same goes for $x & 0xff meaning "give me the last 8 bits"

In my personal opinion, the worst offender in the whole Perl ecosystem when it comes to "magic numbers" is the default variable $_. It has no fixed value, and the perl interpreter pops it silently into your code whenever you forget to specify a variable.