I don't have too much more to add except that I laud your decision to replace the use of backticks with an alternate approach. There are just too many pitfalls involved with calling out to an external command and interpreting its output. In particular, using backticks with string interpolation like you are doing is especially problematic. What happens, for example, if $dir contains a space?

If you have other uses of backticks in your program, I would strongly encourage you to replace them with more robust solutions. I wish I could point you to a good writeup of the best practices in this regard, but unfortunately I don't know of any right now.