The bottom of the date(1) man page has `date -j -f "%a %b %d %T %Z %Y" "`date`" "+%s"`, but it does not document the meaning of the format specifers. It would be nice if the date command had documentation on the format specifiers to it.
you should submit this upstream
# man date ... > The format string may contain any of the conversion specifications described in the strftime(3) manual page, as well as any arbitrary text.
*** This bug has been marked as a duplicate of bug 419473 ***
(In reply to comment #2) > # man date > ... > > The format string may contain any of the conversion specifications described in the strftime(3) manual page, as well as any arbitrary text. closing as upstream (or maybe invalid)