Date input formats (GNU Coreutils 9.0)
29 Date input formats
First, a quote:
Our units of temporal measurement, from seconds on up to months, are so complicated, asymmetrical and disjunctive so as to make coherent mental reckoning in time all but impossible. Indeed, had some tyrannical god contrived to enslave our minds to time, to make it all but impossible for us to escape subjection to sodden routines and unpleasant surprises, he could hardly have done better than handing down our present system. It is like a set of trapezoidal building blocks, with no vertical or horizontal surfaces, like a language in which the simplest thought demands ornate constructions, useless particles and lengthy circumlocutions. Unlike the more successful patterns of language and science, which enable us to face experience boldly or at least level-headedly, our system of temporal calculation silently and persistently encourages our terror of time.
… It is as though architects had to measure length in feet, width in meters and height in ells; as though basic instruction manuals demanded a knowledge of five different languages. It is no wonder then that we often look into our own immediate past or future, last Tuesday or a week from Sunday, with feelings of helpless confusion. …
—Robert Grudin, Time and the Art of Living.
This section describes the textual date representations that GNU programs accept. These are the strings you, as a user, can supply as arguments to the various programs. The C interface (via the
parse_datetime function) is not described here.
|• General date syntax||Common rules|
|• Calendar date items||21 Jul 2020|
|• Time of day items||9:20pm|
|• Time zone items||UTC, -0700, +0900, …|
|• Combined date and time of day items||2020-07-21T20:02:00,000000-0400|
|• Day of week items||Monday and others|
|• Relative items in date strings||next tuesday, 2 years ago|
|• Pure numbers in date strings||20200721, 1440|
|• Seconds since the Epoch||@1595289600|
|• Specifying time zone rules||TZ="America/New_York", TZ="UTC0"|
|• Authors of parse_datetime||Bellovin, Eggert, Salz, Berets, et al.|