TempleOS

kill -9 $(pidof <process>)

Btw also an awesome way of telling people you’re pregnant.

fyi, systemctl disable/enable has a --now flag

Probably, from what I can see the address in question isn’t really that exotic. but an email regex that validates 100% correctly is near impossible. And then you still don’t know if the email address actually exists.

I’d just take the user at their word and send an email with an activation link to the address that was supplied. If the address is invalid, the mail won’t get delivered. No harm done.