`--separate-git-dir=<git-dir>`::
Instead of initializing the repository as a directory to either `$GIT_DIR` or
`./.git/`, create a text file there containing the path to the actual
repository.  This file acts as a filesystem-agnostic Git symbolic link to the
repository.
+
If this is a reinitialization, the repository will be moved to the specified path.

`-b <branch-name>`::
`--initial-branch=<branch-name>`::
Use _<branch-name>_ for the initial branch in the newly created
repository.  If not specified, fall back to the default name (currently
`master`, but this is subject to change in the future; the name can be
customized via the `init.defaultBranch` configuration variable).

`--shared[=(false|true|umask|group|all|world|everybody|<perm>)]`::

Specify that the Git repository is to be shared amongst several users.  This
allows users belonging to the same group to push into that
repository.  When specified, the config variable `core.sharedRepository` is
set so that files and directories under `$GIT_DIR` are created with the
requested permissions.  When not specified, Git will use permissions reported
by `umask`(2).
+
The option can have the following values, defaulting to `group` if no value
is given:
+
--
`umask`::
`false`::

Use permissions reported by `umask`(2). The default, when `--shared` is not
specified.

`group`::
`true`::

Make the repository group-writable, (and `g+sx`, since the git group may not be
the primary group of all users). This is used to loosen the permissions of an
otherwise safe `umask`(2) value. Note that the umask still applies to the other
permission bits (e.g. if umask is `0022`, using `group` will not remove read
privileges from other (non-group) users). See `0xxx` for how to exactly specify
the repository permissions.

`all`::
`world`::
`everybody`::

Same as `group`, but make the repository readable by all users.

_<perm>_::

_<perm>_ is a 3-digit octal number prefixed with `0` and each file
will have mode _<perm>_. _<perm>_ will override users' `umask`(2)