> i use xlswrite to write in Excel
> but it's possiible to color some cells of the sheet?
Sure it is possible but not using the code in the io package; that code only
serves to interchange data between Octave and spreadheet files.
You'd have to write your own code, using (if your platform is Windows and
you use the windows package and Excel) VBA as Sebastian suggests, or using
Java methods for the Java-based interfaces.The javadocs for e.g. Apache POI,
jOpenDocument etc etc have clear descriptions.