$ perl -e'
   use v5.40;

   use Symbol      qw( gensym );
   use Tie::Simple qw( );

   my $fh = gensym;

   tie *$fh, Tie::Simple::, undef,
      PRINT => sub {
         shift;
         my $msg = join( defined( $, ) ? $, : "", @_ );
         $msg .= $\ if defined( $\ );
         say STDOUT "[$msg]";
      };

   say $fh "Hello!";
'
[Hello!
]