This gives the expected result now -- both on Moar and JVM, both for REPL and command line execution via '-e':
$ perl6-m -e 'my $lines = +qx[tput lines]; my $cols = +qx[tput cols]; say "$lines $cols";' 65 199 $ perl6-j -e 'my $lines = +qx[tput lines]; my $cols = +qx[tput cols]; say "$lines $cols";' 65 199 $ perl6-m > my $lines = +qx[tput lines]; my $cols = +qx[tput cols]; say "$lines $cols"; 65 199 $ perl6-j > my $lines = +qx[tput lines]; my $cols = +qx[tput cols]; say "$lines $cols"; 65 199 True I don't know what the underlying problem was, so I have no idea how a proper test could look like.