What version of "date(1)" are you talking about? My version (MacOSX/darwin, based on bsd) doesn't have a "-d" option at all, and on a freebsd machine, "-d" means "set the kernel's value for daylight savings time". (Looks like the Solaris 5.8's "date" didn't have "-d" either, and on a linux box, "-d STRING" doesn't seem to report seconds since epoch, but date +%s does.)