perl -MAstro::Montenbruck::Time=jdnow,jd2mjd,jd_cent -e '$|++;print sprintf("%-22s","Julian day").sprintf("%-22s","Modified Julian day").sprintf("%-22s","Julian centuries since J2000.0")."\n";while(){$j=jdnow();print"\r".sprintf("%-22s",$j).sprintf("%-22s",jd2mjd($j)).sprintf("%-22s",jd_cent($j));sleep 1}'