There are several existing tools for searching for Unicode characters. I have generally used Xah Lee’s one but I wanted to write my own so that I wasn’t just relying on some random guy I didn’t know. I decided that as it would need a GUI it would be a good project for learning Javascript. I ended up using basically the same code for the back-end search in three different tools: there’s a desktop application that uses Electron, the same in a web page on this very site, and a command-line tool.

Perl has great support for UTF-8, but you need to be careful because of its dedication to backward compatibility and lots of old code that is still out there. This will hopefully help you avoid some of the pitfalls, and give you some tips to figure out what is wrong with other peoples’ code that you have to debug.