t / t4013 / diff.diff-tree_--root_--abbrev_initialon commit setup: set env $GIT_WORK_TREE when work tree is set, like $GIT_DIR (d95138e)
   1$ git diff-tree --root --abbrev initial
   2444ac553ac7612cc88969031b02b3767fb8a353a
   3:000000 040000 0000000... da7a33f... A  dir
   4:000000 100644 0000000... 01e79c3... A  file0
   5:000000 100644 0000000... 01e79c3... A  file2
   6$