This command is wrapped in a CMPITclPackagedCommand.
It is part of the spectrum package (CSpectrumPackage).
It only actually does something in the MPI_EVENT_SINK_RANK
process as it requires a histogramer and displayer into which to load
the spectrum and, if necessary, bind it to display memory. Note
that spectra read in from file are only known to the
MPI_EVENT_SINK_RANK process though I believe that they
will show up in the spectrum list and be handled properly by most
commands.