[rb-general] using SOURCE_DATE_EPOCH with date

[Bernhard M. Wiedemann]

Hi

what is the best way to use SOURCE_DATE_EPOCH with date?

I found
date ${SOURCE_DATE_EPOCH/#/--date=}
to be quite elegant, but it does not work with dash.

date --date=@${SOURCE_DATE_EPOCH:-$(date +%s)}
does work with dash and bash, but is not as nice.

Also there are longer variants like
https://github.com/jackaudio/jack2/pull/196/files

that would not look nice when used in Makefiles.
Can you think of better ways than these?
And which one(s) should we recommend for patches we send upstream?

Ciao
-- 
Bernhard M. Wiedemann
software engineer