$ git diff-tree --root -r --abbrev initial
444ac553ac7612cc88969031b02b3767fb8a353a
:000000 100644 0000000 35d242b A	dir/sub
:000000 100644 0000000 01e79c3 A	file0
:000000 100644 0000000 01e79c3 A	file2
$