A more complete explanation of Regular Expressions in Email Parser

The topic that explains the use of Regular Expressions was very brief and just pointed to other useful resources on the net. Since questions regarding Regular Expressions are frequent this topic has been completed with more examples, a step-by-step tutorial that covers the basics and also how capture groups are used in the context of Email Parser. I would like to also point here to a very interesting question that the user “logo11” has posted. If you are curious about how Regular Expressions are implemented in Email Parser it is worth a look.