15.64.31.8  FILE   - FILE=filename  -  Selects the filename to restore the
histograms from.  If IDENT is specified then  the  selected  histogram  is
fetched  from  the  file.   If  the  filename is NONE then no file name is
selected.  If the filename is blank (FILE='') then the last opened file is
used, or if none has been opened.
     HBOOK.BIN - For HBOOK4 direct access files.

                                  example
     TD:SET HIST FILE=MY_HISTS.BIN
Gets the histograms from file MY_HISTS.BIN.
     TD:SET HIST FILE="MY_HISTS.BIN;1"
Gets histograms from the first version of the file.