date: `--date` always results in invalid date

[BuriedInTheGround]

As the title says, everything I tried to pass to the --date option results in invalid date.

$ date --version
date 0.0.7
$ date --date="Sun, 29 Feb 2004 16:21:42 -0800"
date: invalid date 'Sun, 29 Feb 2004 16:21:42 -0800'
$ date --date="@1631716521"
date: invalid date '@1631716521'

I am currently using the version 0.0.7 on NixOS 20.05.

Also, thanks for all your work!

[blyxxyz]

It currently uses chrono's parsing, which is very strict, something like a subset of ISO-8601. These are accepted:

date --date="1970-01-01T00:00:00Z"
date --date="1970-01-01T00:00:00+01:00"

(It doesn't seem to do anything with the timezone afterwards, though.)

[BuriedInTheGround]

Ah, okay! Thanks for the info. If this issue should be closed, you can do it or just let me know.

For others with a problem similar to mine: if you need to convert a unix epoch to retrieve the time between two moments, something like the following works good.

date --date="$(TZ=Etc/GMT printf '1970-01-01%(T%H:%M:%S)T+00:00\n' 12345)" -u +%H:%M

Specifically, I needed this to make this polybar script work.

[PedroHLC]

Any trick for having relative dates? (E.g: all the ones visible here: https://www.cyberciti.biz/tips/linux-unix-get-yesterdays-tomorrows-date.html)

[tertsdiepraam]

I can't find any relative date support in the code, but it's definitely something we should support, so feel free to open an issue for it!