$ git diff-tree --root -r --abbrev=4 initial
444ac553ac7612cc88969031b02b3767fb8a353a
:000000 100644 0000 35d2 A dir/sub
:000000 100644 0000 01e7 A file0
:000000 100644 0000 01e7 A file2
$
$ git diff-tree --root -r --abbrev=4 initial
444ac553ac7612cc88969031b02b3767fb8a353a
:000000 100644 0000 35d2 A dir/sub
:000000 100644 0000 01e7 A file0
:000000 100644 0000 01e7 A file2
$