use utf8;
use Encode;

$\ = "\n";
my $unicodeScalar = "Je suis une chaîne accentuée là où il faut.";
my $cmdLineArg = $ARGV[0];
my $stdInLine = <STDIN>;

print '['.Encode::is_utf8($unicodeScalar).'] '.$unicodeScalar;
print $unicodeScalar;
print '['.Encode::is_utf8($cmdLineArg).'] '.$cmdLineArg;
print '['.Encode::is_utf8($stdInLine).'] '.$stdInLine;