... SFIT is a general-purpose code designed to optimize theoretical stellar spectra to an observed spectrum. ... While the programme expects input from "stdio", it is more natural to save commands in a file (eg "sfit_input") and run the code simply by . ... If the spectra to be fitted have a filename "star_spectrum", then the best fit spectrum will be written out, together with the renormalized input spectrum, to a file called "star_spectrum.fit". ... sets up model spectrum grid (and for 2nd star) . ...