update command line reference

docs/reference.md

@@ -2,29 +2,42 @@
 
 ## Module Options
 
-TODO: Still to be documented
+We are currently having issues beeing able to generate proper
+module option documentation for our recursive disko types.
+However you can read the available options [here](https://github.com/nix-community/disko/tree/master/lib/types).
+Combined wit the [examples](https://github.com/nix-community/disko/tree/master/example) this hopefully gives you an overview.
 
 ## # Reference Manual: disko
 
 ## Command Line Options
 
 ```
-$ nix run github:nix-community/disko --
-disko [options] disk-config.nix
-or disko [options] --flake github:somebody/somewhere
+Usage: ./disko [options] disk-config.nix
+or ./disko [options] --flake github:somebody/somewhere#disk-config
+
+With flakes, disk-config is discovered first under the .diskoConfigurations top level attribute
+or else from the disko module of a NixOS configuration of that name under .nixosConfigurations.
+
 Options:
+
 * -m, --mode mode
-  set the mode, either create or mount
+  set the mode, either format, mount or disko
+    format: create partition tables, zpools, lvms, raids and filesystems
+    mount: mount the partition at the specified root-mountpoint
+    disko: first unmount and destroy all filesystems on the disks we want to format, then run the create and mount mode
 * -f, --flake uri
   fetch the disko config relative to this flake's root
 * --arg name value
   pass value to nix-build. can be used to set disk-names for example
 * --argstr name value
   pass value to nix-build as string
-* --root-mountpoint /mnt
-  where to mount the device tree
+* --root-mountpoint /some/other/mnt
+  where to mount the device tree (default: /mnt)
 * --dry-run
   just show the path to the script instead of running it
+* --no-deps
+  avoid adding another dependency closure to an in-memory installer
+    requires all necessary dependencies to be available in the environment
 * --debug
   run with set -x
 ```