Apart from that, there are many conventions and styles, and each comes with its reasoning.

CamelCase vs. underline_variables, hungarian notation (I mean the original one) etc... pick what best suits you.

For programming perl, in what concerns variables, apart from perlstyle I personally agree with points 20-22 of Abigail's coding guidelines, which - as per your example - I would extend as

• declare variables early in the scope in which they are used
• declare variables as close as possible to their first use in their scope
• resolve contradictions of these conflicting rules by looking at the importance of those variables, and their frequency and location of usage

Which means that e.g. if there are variables that are used only in a particular fragment of their scope, declare them at the beginning of that fragment. If they are important for what the block (scope, file) is all about, declare them up front.

If there's a great distance (measured in screen pages) between the declaration of variables and their use, add a short comment indicating the first occurence of their use.

--shmem

update: added readability to first rule

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}