$* <<EOI >>EOO          # file
cmd 0<<<a 1>>>b 2>>>&c
EOI
cmd <<<a >>>b 2>>>&c
EOO

$* <<EOI >>EOO          # out-merge1
cmd 1>&2
EOI
cmd >&2
EOO

$* <<EOI >>EOO          # out-merge2
cmd 1>&2 2>&1 2>a
EOI
cmd >&2 2>a
EOO

$* <<EOI 2>>EOE != 0    # out-merge-fail1
cmd 1>&a
EOI
testscript:1:8: error: stdout merge redirect file descriptor must be 2
EOE

$* <<EOI 2>>EOE != 0    # out-merge-fail2
cmd 1>&1
EOI
testscript:1:8: error: stdout merge redirect file descriptor must be 2
EOE

$* <<EOI 2>>EOE != 0    # out-merge-fail3
cmd 1>&
EOI
testscript:1:8: error: missing stdout file descriptor
EOE

$* <<EOI >>EOO          # err-merge1
cmd 2>&1
EOI
cmd 2>&1
EOO

$* <<EOI >>EOO          # err-merge2
cmd 1>&2 2>&1 >a
EOI
cmd >a 2>&1
EOO

$* <<EOI 2>>EOE != 0    # err-merge-fail1
cmd 2>&2
EOI
testscript:1:8: error: stderr merge redirect file descriptor must be 1
EOE

$* <<EOI 2>>EOE != 0    # err-merge-fail2
cmd 2>&2
EOI
testscript:1:8: error: stderr merge redirect file descriptor must be 1
EOE

$* <<EOI 2>>EOE != 0    # err-merge-fail3
cmd 2>&
EOI
testscript:1:8: error: missing stderr file descriptor
EOE

$* <<EOI 2>>EOE != 0    # merge-fail1
cmd 1>&2 2>&1
EOI
testscript:1:14: error: stdout and stderr redirected to each other
EOE