From curt@tilmes.org

% perl6 -e 'my $proc = run "cat", :in, :out; $proc.in.say​: "test\n"; say
$proc.out.get; $proc.in.close;'
test

% perl6 -e 'my $proc = run "cat", :in, :out; say
$proc.out.native-descriptor; $proc.in.say​: "test\n"; say $proc.out.get;
$proc.in.close;'
28
Nil

From @AlexDaniel

  Some *able info, if anyone is interested​:

  Output on all releases​: https://gist.github.com/a68b094519839b939f8c70d66a80d8c0
 
  Some possibly relevant commits​:
  rakudo/rakudo@92bd7e4
  rakudo/rakudo@6dae179
 
  On 2017-11-22 11​:26​:59, curt@​tilmes.org wrote​:
  > % perl6 -e 'my $proc = run "cat", :in, :out; $proc.in.say​: "test\n"; say
  > $proc.out.get; $proc.in.close;'
  > test
  >
  > % perl6 -e 'my $proc = run "cat", :in, :out; say
  > $proc.out.native-descriptor; $proc.in.say​: "test\n"; say $proc.out.get;
  > $proc.in.close;'
  > 28
  > Nil
 
 
   

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