When fsv is invoked with the --help option, it prints out a usage summary:
| bash$ fsv2 --help
Usage: fsv2 [rootdir] [options]
  rootdir      Root directory for visualization
               (defaults to current directory)
  --mapv       Start in Map View mode (default)
  --treev      Start in TreeV mode
  --help       Print this help and exit
fsv2 - 3D File System Visualizer v.1.1.0 | 
Options and arguments
Specifies the base of the directory tree for fsv to work in. Everything inside this directory will be scanned, and subsequently translated into geometry.
If no value is given, fsv works in the directory it is invoked from.
--mapvStarts the program in Map View visualization mode. (This is the default)
--treevStarts the program in Tree View visualization mode.
--helpPrints out the usage summary and exits.