The regular expression subject is a complex one. I've been wondering whether I should try and pass on what I know about it. 

Strictly this brace expansion topic is in the area of using patterns to match filenames. Confusingly this is similar but not the same as regular expressions. In later episodes in this (not-)series I want to talk more about filename matching then look at regular expressions in the context of Bash.

Really, the regular expression subject could (should?) be stand-alone and should look at what's available in Bash, grep, sed, awk, etc. I use Perl regular expresions the most but I hesitate to go too deep there because they are mind-blowing :-)