Sieve is a mail filtering language you can look into. For Unix there are many tools with filtering as this is an old problem Fdm, procmail, maildrop Unfortun

Sieve is a mail filtering language you can look into. For Unix there are many tools with filtering as this is an old problem Fdm, procmail, maildrop Unfortunately despite just being text, email has become a monolithic black box for most which limits what you can do with the text.