java - Is there an implementable (non-theoretical) way to prove if email address belong to real email account? -

is there way prove email address "real", therefore belongs existing email account ? masses of registrations via emails valid according email pattern definition, not exist. sending fake mail addresses costs lot of money, (and others) pay per mail (100.000 sendings fake mail accounts can cost four-digit numbers per year, show number). i want check moment. don't care if email adress offline 1 minute later.

an ideal solution bash one-liner (that called every major language).

what have done far:

1. checking this similar 3yo thread, wrong real-world case. want check if email adress exist, in moment i'm sending mail (to prevent costs).
2. checking if hostname pingable.
3. checking if email adress pingable, here. tried rebuild in bash script, failed (fetching adress hard!).

what want:

a reliable check if mail account exists implementable average coder, in php or java. bash one-liner or php/java library this. free or commercial.

i'll provide bounty!

it's called "double opt-in".

1. the user enters email address in registration form.
2. the user clicks box says "yes, please email me".
3. you send email user along lines of "hi, confirm account. please click this link."
4. once link clicked have confirmation you're ever going get, , you're less either spammer, or mistaken one.

other such magic spells not wasting paid emails are:

• "using mailer knows 500-level smtp error means" [aka, not mail()] , deleting person list.
• "bounce processing" , deleting person list.
• "a working unsubscribe process" works, , deletes person list. did mention should work?

if [or reading this] have not gathered email lists voluntarily without @ least some level of user opting in there's advanced technique email admins call "pissing rope" hang length of rope high place , see how high directly beneath it.