add a -j flag that tells date not to try to set the date. This allows you
to use date as a userland interface to strptime.
example:
TZ=GMT date -j -f "%a, %d %b %Y %T %Z" "Sun, 08 Nov 1998 02:22:20 GMT" +%s
which is the standard format for Last-modified headers in HTTP requests.
only one to respond: eivind