1 ROOT_OPEN
  Syntax: ROOT_OPEN filename
  where   filename  is the name of the file to open.

  Opens an ROOT file. Unlike `HB_OPEN' this command is necessary for ROOT, as
  the filename cannot be specified in the `ROOT_FETCH' command. Use the
  commands `CDIR' and `LDIR' (or `SET DIRECTORY' and `SHOW DIRECTORY') to
  change directories or list directroy contents. The root file will have the
  directory name `//root', so use the command `cd //root' to chnage to the
  top-level directory. You can then find out what histograms are in a file and
  fetch histograms from several subdirectories and give them separate
  secondary identifiers.

  This command is only available is Mn_Fit has been compiled with the ROOT
  interface turned on.

