cdfj −− convert from normal date to Julian day or vice versa
cdfj julian_day
cdfj day month year
Cdfj converts the Julian day specified on the command line to the corresponding day, month, and year. Alternatively, if the day, month, and year are specified, conversion is made to Julian day. The answer appears on the standard output.
The conversion algorithms were obtained from the CDF Implementer’s Guide, Version 1, by Michael L. Gough, NASA/NSSDC. This publication references
Fleigel, H. F., and T. C. Van Flandern, 1968, Communications ACM, 11, 657.