If you want to go from x and y position on a frame to ra and dec using the WCS in the header, here's how to do it:
wcsctran STDIN STDOUT f2.fits logical world col="1 2" formats="%12.2H %12.1h"
If you instead want to read the data from a file, or write to a file, replace STDIN and STDOUT with the appropriate file names, and modify "col" to reflect which columns the x and y values are in.
To go the other way:
wcsctran STDIN STDOUT f2.fits world logical col="1 2" units="h n" formats="%8.3f %8.3f"