IGU -- Grid file utility
  IGU LIST bgridf egridf <keywords>
  IGU SET gridf
  IGU COPY sgridf dgridf RENUMBER
  IGU MAKE gridf maxgrd "text
  IGU DEL bgridf egridf
  IGU DIR gridf date project "text
Parameters:
  LIST | lists a directory on the text frame
  DEL | deletes a grid file
  SET | sets the current grid file number
  COPY | copies a grid file
  MAKE | generates a grid file
  DIR | modifies a directory for a grid file
  RENUMBER | renumbers grids after copying a file
  gridf | grid file number
  bgridf | beginning grid file number
  egridf | ending grid file number
  sgridf | source grid file number
  dgridf | destination grid file number
  date  | date the grid file was generated (def=current)
  project | project number (def=current project number)
  maxgrd | maximum number of grids in the grid file
  "text | identification text for your grid file; double quote mandatory
Keywords:
  DAY= | list the grid files with this date or range of dates, YYDDD
  PROJ= | list the grid files with this project number or range of
          project numbers.
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