I realize that this question has been asked many times, but I've yet to find a flatfile version.
I'm looking for a way to achieve this:
A person submits their email address via a form.
The email is then stored in flatfile database (.txt)
The person then gets an auto-reply email with a link to confirm their email address.
Upon confirming after clicking the link, their email address is saved to a new file (confirmed_emails.txt for example).
Is this possible without the use of a SQL/similar datase, and how can I achieve this?
Note: SQL or other database option, is not an option unfortunately.