[--cacheinfo <mode> <object> <file>]\*
[--chmod=(+|-)x]
[--assume-unchanged | --no-assume-unchanged]
+ [--ignore-submodules]
[--really-refresh] [--unresolve] [--again | -g]
[--info-only] [--index-info]
[-z] [--stdin]
default behavior is to error out. This option makes
git-update-index continue anyway.
+--ignore-submodules:
+ Do not try to update submodules. This option is only respected
+ when passed before --refresh.
+
--unmerged::
If --refresh finds unmerged changes in the index, the default
behavior is to error out. This option makes git-update-index