Hi Frank,

Regular expressions are a language in their own right. It's not a trivial concept to get your head around. However, learning how to use them is very rewarding because they are everywhere.

I used to use procmail for my mail back in the days when the university I worked at first connected to the internet and had access to TCP/IP and SMTP mail. (Prior to that we'd used DECMail and the UK "Coloured Book" networking protocols). I found the regular expressions in procmailrc challenging, but gradually got the hang of them.

I just posted the last episode of this series, number 5, today. I hope you make your way through them all and find them useful.