I have hardly ever used tr but I bumped into it the other day when looking something else up in the Camel Book. I thought that it could be useful for just the thing you are doing. It would be interesting to benchmark the various ways of counting characters or strings within strings.

Regarding q{} and qq{}, I am from a *nix background and had never had any problem with normal single- and double-quotes. Then I started trying to do one-liners under MS Windoze and struggled. The quoting operators made it all work nicely and since then, to avoid having to think where I am, I have got into the habit of using them all the time. I don't think that there is any particular merit either way other than normal quotes are widely familiar and take fewer keystrokes, quoting operators do the right thing at the DOS prompt.

Cheers,

JohnGG