Debian commonly uses the date+time format specified in RFC 2822 for text date+time values in computer-parseable data.

However, there are formats with arguably better properties of both universality and parseability, namely those of ISO 8601 and derivatives like W3CDTF and RFC 3339 specifications.

This page discusses the proposal to change Debian's preferred date+time format to an ISO 8601 profile.

I don't think there's any reason to use the obsolete RFC 2822 time format in new standards. -- ?TeemuIkonen

In increasing order of precision and verbosity, the commands to get ISO 8601 date+time values (-- BenFinney):

$ date +'%F'
$ date +'%FT%T'
$ date +'%FT%T%:z'