Options and their meanings are:
-I Identify program and exit.
-i item Select input item.
-w window Specify the analysis window size in seconds. Default: 0.020s.
-c Perform cepstral smoothing on the resulting spectrum.
-P Do not pre-emphasise the signal prior to analysis.
-a anlabel Specify an annotation label that specifies a time at which to calculate the spectrum.
-t time Specify the time at which to calculate the spectrum.
-T timefile Specify a file containing times (one per line) at which to calculate a number of spectra. If filename is given as '-', then the times are read from the standard input.
-n Normalise the spectrum by subtracting the mean dB value from each frequency.
-m Calculate the mean spectrum when more than one spectrum is calculated.
-p Send the resulting graph directly to the printer.
-f maxfreq Set maximum frequency for displayed graph.
SP.xx Any speech item.
AN.xx (Optional) Any annotation item.