analogue_gain - Change the analogue gain setting (for EXOSAT ME).
area - Change the effective area of the detector.
background - Change the background file name.
bad_chan - Indicate the channels in a grouping card to be easily ignored in XSPEC.
bsf - Change the background scaling factor.
change - Change pha_data into pha_per_sec.
collimator - Change the collimator efficiency.
correction - Change the correction file name.
csf - Change the scaling factor for the correction file.
detid - Change the detector ID.
end_time - Change the end time.
exit - Write a new PHA file and exit.
gain_coeff - Change the gain coefficients (EXOSAT ME, GSPC).
group - Rebin a spectrum.
help - Obtain help on CHANPHA options.
indices - Change indices (3 values).
prefix - Prefix a current output file name.
quit - Exit the program without writing new a PHA file.
resolution_coeff - Change the resolution coefficients (EXOSAT ME).
response - Change the response file name.
start_time - Change the start time.
systematics - Create a new systematic error package.
time - Change the active integration time.
write - Write a new PHA file.
*nbin - Change the no. of channels in file.
*nchan - Change the no. of detector channels (unbinned).
*pha_data -
*pha_per_sec -
*pha_per_cm2s -
*pha_errors - Write your own data (e.g. if data in ASCII file).
The commands starting with a 
are currently under development and
will finally allow the user to read data from an ASCII file into an
existing file in XSPEC format.
The commands change various entries in different packages in the data file. For more information on the packages and their contents see §7.1.