[13:48:33] ~/test$ cat a
12345678901234567890äöüäöüäöüäöüäöüäöüäö
[13:48:39] ~/test$ hexdump -C a
00000000  31 32 33 34 35 36 37 38  39 30 31 32 33 34 35 36  |1234567890123456|
00000010  37 38 39 30 c3 a4 c3 b6  c3 bc c3 a4 c3 b6 c3 bc  |7890............|
00000020  c3 a4 c3 b6 c3 bc c3 a4  c3 b6 c3 bc c3 a4 c3 b6  |................|
00000030  c3 bc c3 a4 c3 b6 c3 bc  c3 a4 c3 b6 0a           |.............|
0000003d
[13:48:42] ~/test$ perl -MEncode -wE'open my $FH, "<:utf8", "a" or die $!; my @entries = do { local $/ = \5; <$FH> }; say encode_utf8($_) for @entries;'
12345
67890
12345
67890
äöüäö
üäöüä
öüäöü
äöüäö