treeish
	tree hashes
commitish
	commit hashes

- full SHA1
- partial SHA1
- branch, remote or tag name
  (adding a date spec like @{yesterday} or @{1 mongh ago}, @{5} 5 prior values...)
- carrot parents (history)
  <hash>^
    one commit back (parent)
  <hash>^2
    second parent (in case if <hash> is a merge commit)
  <hash>^^
    two ...
  <hash>~5
    five ...
- tilde specs
  master~2
    2nd generation grandparent of master (grandparent)
- tree spec
  master^{tree}
    tree that 'master' points to (tree object, usefull for running ls-tree)
- blob spec
  master:/path/to/file
    if you need a certain file of the 'master' commit
- ranges
  <hash1>..<hash2>
    between ... note - branches can also be used here.
  <hash1>..
    everything since a commit