docs: def main():
      """
      NAME
          thellier_magic.py
  
      DESCRIPTION
          plots Thellier-Thellier data in version 3.0 format
          Reads saved interpretations from a specimen formatted table, default: specimens.txt
  
      SYNTAX
          thellier_magic.py [command line options]
  
      OPTIONS
          -h prints help message and quits
          -f MEAS, set measurements input file, default is 'measurements.txt'
          -WD: directory to output files to (default : current directory)
               Note: if using Windows, all figures will output to current directory
          -ID: directory to read files from (default : same as -WD)
          -fsp PRIOR, set specimens.txt prior interpretations file, default is 'specimens.txt'
          -fmt [svg,png,jpg], format for images - default is svg
          -sav,  saves plots without review (in format specified by -fmt key or default)
          -spc SPEC, plots single specimen SPEC, saves plot with specified format
              with optional -b bounds and quits
          -n SPECIMENS, number of specimens to plot
  
      OUTPUT
          figures:
              ALL:  numbers refer to temperature steps in command line window
              1) Arai plot:  closed circles are zero-field first/infield
                             open circles are infield first/zero-field
                             triangles are pTRM checks
                             squares are pTRM tail checks
                             VDS is vector difference sum
                             diamonds are bounds for interpretation
              2) Zijderveld plot:  closed (open) symbols are X-Y (X-Z) planes
                                   X rotated to NRM direction
              3) (De/Re)Magnetization diagram:
                             circles are NRM remaining
                             squares are pTRM gained
              4) equal area projections:
                 green triangles are pTRM gained direction
                             red (purple) circles are lower(upper) hemisphere of ZI step directions
                             blue (cyan) squares are lower(upper) hemisphere IZ step directions
              5) Optional:  TRM acquisition
              6) Optional: TDS normalization
          command line window:
              list is: temperature step numbers, temperatures (C), Dec, Inc, Int (units of measuements)
                       list of possible commands: type letter followed by return to select option
                       saving of plots creates image files with specimen, plot type as name
      """
  
  #
  # parse command line options
  #
  
      if '-h' in sys.argv:
          print(main.__doc__)
          sys.exit()
      dir_path = pmag.get_named_arg("-WD", default_val=".")
      input_dir_path = pmag.get_named_arg('-ID', "")
      input_dir_path, dir_path = pmag.fix_directories(input_dir_path, dir_path)
      meas_file = pmag.get_named_arg(
          "-f", default_val="measurements.txt")
      #spec_file = pmag.get_named_arg(
      #    "-fsp", default_val="specimens.txt")
      #crit_file = pmag.get_named_arg("-fcr", default_val="criteria.txt")
      #spec_file = os.path.join(dir_path, spec_file)
      #crit_file = os.path.join(dir_path, crit_file)
      meas_file = pmag.resolve_file_name(meas_file, input_dir_path)
      fmt = pmag.get_named_arg("-fmt", "svg")
      save_plots = False
      interactive = True
      if '-sav' in sys.argv:
          save_plots = True
          interactive=False
      spec = pmag.get_named_arg("-spc", default_val="")
      n_specs = pmag.get_named_arg("-n", default_val="all")
      try:
          n_specs = int(n_specs)
      except ValueError:
          pass
      ipmag.thellier_magic(meas_file, dir_path, input_dir_path,
                           spec, n_specs, save_plots, fmt, interactive)