Documentation / fetch-options.txton commit Update howto using-topic-branches (f37d0cc)
   1-a, \--append::
   2        Append ref names and object names of fetched refs to the
   3        existing contents of `.git/FETCH_HEAD`.  Without this
   4        option old data in `.git/FETCH_HEAD` will be overwritten.
   5
   6-f, \--force::
   7
   8-t, \--tags::
   9        By default, the git core utilities will not fetch and store
  10        tags under the same name as the remote repository;  ask it
  11        to do so using `--tags`.
  12
  13-u, \--update-head-ok::
  14        By default `git-fetch` refuses to update the head which
  15        corresponds to the current branch.  This flag disables the
  16        check.  Note that fetching into the current branch will not
  17        update the index and working directory, so use it with care.