input = "@extract.lis"  List of input images
        nfind = 1               Number of apertures to be found automatically
      (output = "")             List of output spectra
   (apertures = "")             Apertures
      (format = "multispec")    Extracted spectra format
  (references = "")             List of aperture reference images
    (profiles = "")             List of aperture profile images\n
 (interactive = yes)            Run task interactively?
        (find = yes)            Find apertures?
    (recenter = yes)            Recenter apertures?
      (resize = yes)            Resize apertures?
        (edit = yes)            Edit apertures?
       (trace = yes)            Trace apertures?
    (fittrace = yes)            Fit the traced points interactively?
     (extract = yes)            Extract spectra?
      (extras = yes)            Extract sky, sigma, etc.?
      (review = yes)            Review extractions?\n
        (line = INDEF)          Dispersion line
        (nsum = 50)             Number of dispersion lines to sum or median\n\n
       (lower = -8.)            Lower aperture limit relative to center
       (upper = 8.)             Upper aperture limit relative to center
   (apidtable = "")             Aperture ID table (optional)\n\n# DEFAULT BACKG
  (b_function = "chebyshev")    Background function
     (b_order = 1)              Background function order
    (b_sample = "-20:-10,10:20") Background sample regions
  (b_naverage = -100)           Background average or median
  (b_niterate = 0)              Background rejection iterations
(b_low_reject = 3.)             Background lower rejection sigma
(b_high_rejec = 3.)             Background upper rejection sigma
      (b_grow = 0.)             Background rejection growing radius\n\n# APERTU
       (width = 5.)             Profile centering width
      (radius = 10.)            Profile centering radius
   (threshold = 0.)             Detection threshold for profile centering\n\n# 
      (minsep = 5.)             Minimum separation between spectra
      (maxsep = 1000.)          Maximum separation between spectra
       (order = "increasing")   Order of apertures\n\n# RECENTERING PARAMETERS\n
  (aprecenter = "")             Apertures for recentering calculation
      (npeaks = INDEF)          Select brightest peaks
       (shift = yes)            Use average shift instead of recentering?\n\n# 
      (llimit = INDEF)          Lower aperture limit relative to center
      (ulimit = INDEF)          Upper aperture limit relative to center
      (ylevel = 0.5)            Fraction of peak or intensity for automatic wid
        (peak = yes)            Is ylevel a fraction of the peak?
         (bkg = yes)            Subtract background in automatic width?
      (r_grow = 0.)             Grow limits by this factor
   (avglimits = no)             Average limits over all apertures?\n\n# TRACING
      (t_nsum = 50)             Number of dispersion lines to sum
      (t_step = 50)             Tracing step
     (t_nlost = 3)              Number of consecutive times profile is lost bef
  (t_function = "legendre")     Trace fitting function
     (t_order = 2)              Trace fitting function order
    (t_sample = "*")            Trace sample regions
  (t_naverage = 1)              Trace average or median
  (t_niterate = 0)              Trace rejection iterations
(t_low_reject = 3.)             Trace lower rejection sigma
(t_high_rejec = 3.)             Trace upper rejection sigma
      (t_grow = 0.)             Trace rejection growing radius\n\n# EXTRACTION 
  (background = "fit")          Background to subtract
      (skybox = 1)              Box car smoothing length for sky
     (weights = "variance")     Extraction weights (none|variance)
        (pfit = "fit1d")        Profile fitting type (fit1d|fit2d)
       (clean = yes)            Detect and replace bad pixels?
  (saturation = 65000.)         Saturation level
   (readnoise = "RO_NOISE")     Read out noise sigma (photons)
        (gain = "RO_GAIN")      Photon gain (photons/data number)
      (lsigma = 4.)             Lower rejection threshold
      (usigma = 4.)             Upper rejection threshold
     (nsubaps = 1)              Number of subapertures per aperture
        (mode = "ql")