$ ncl -h
Usage: ncl -hnpxV  
  -n: don't enumerate values in print()
  -p: don't page output from the system() command
  -o: retain former behavior for certain backwards-incompatible changes
  -x: echo NCL commands
  -V: print NCL version and exit
  -h: print this message and exit

ソースncl_ncarg-6.0.0/ni/src/ncl/Ncl.cを読むと, 二つの隠しオプションがあることが分る。

            /* NOT ADVERTISED!  Will override "no echo" and print EVERYTHING! */
            case 'X':
                NCLoverrideEcho = 1;

            /* NOT ADVERTISED!  Will not echo copyright notice! */
            case 'Q':
                NCLnoCopyright = 1;