Elmer Fudd
Daffy Duck
Alternate
Phone
No
7/13/2017
Yes
9/09/2006
daffy@gmail.com
Elmer.am@gmail.com
12/5/2019
бесполезное.использование.кота@gmail.com
kobernIU@hotmail.comp
drüben@msn.com
manilow@barry76@gmail.com
moc.liamg@نالی بلی
時髦的貓@gmail.com
pen@ничего.net 
last@nothing.nyet
##</code><code>##

#!/usr/bin/perl 

use v5.028;    # strictness implied
use warnings;
use Path::Tiny;
binmode STDOUT, ":utf8";
my $file_in = path("/home/pi/Documents/curate/1.sscce.email.txt");
my $file_out = path('/home/pi/Documents/curate/1.sscce.email.output.txt');
my @lines = $file_in->lines_utf8;
say @lines;
my @matching;
for my $line (@lines){
 
    if ( $line =~ /([A-Za-z0-9._]+\@[a-z0-9.-]+)/){
      push( @matching, $1 );
    }
}

@matching=sort(@matching);
say @matching;
say "cardinality: ", scalar @matching;
my $string = join( " ", @matching );
$file_out->spew_utf8( $string );
__END__