Regex for multiline email addresses?
johnsmith@email.com  - ok

johnsmith@email.com
karensmith@emailcom  - ok

john  smith@email.com - not ok
karensmith@emailcom

((w+([-+.']w+)*@w+([-.]w+)*.w+([-.]w+)*(rn)?)+)r*

^(((w+([-+.']w+)*@w+([-.]w+)*.w+([-.]w+)*(rn)?s?)+)*)$

/Aw+@w+.w+(nw+@w+..w+)*z/

"test@here.plnthe@bar.pl".match(/Aw+@w+.w+(nw+@w+.w+)*z/)
=> #<MatchData "test@here.plnthe@bar.pl" 1:"nthe@bar.pl">
"test@here.plnthebar.pl".match(/Aw+@w+.w+(nw+@w+.w+)*z/)
=> nil
"test@here.pl".match(/Aw+@w+.w+(nw+@w+.w+)*z/)
=> #<MatchData "test@here.pl" 1:nil>
"test@here".match(/Aw+@w+.w+(nw+@w+.w+)*z/)
=> nil