npm install -g dates-tool
dates # prints current time (in several forms)
dates TIME # prints time TIME (in several forms)
dates [+-]DELTA # prints current time offset by DELTA
dates T1 T2 # prints T1, T2, and the delta between them
dates T1 [+-]DELTA # prints T1, DELTA, and T2 = T1 + DELTA
Timestamps can be either integers (which are interpreted as millisecond Unix
epoch times) or a string accepted by JavaScript's Date.parse(). It's
recommended to use ISO 8601 strings for best compatibility.
Deltas can be any integer followed by a suffix "ms", "s", "m", "h", or "d" (for milliseconds, seconds, minutes, hours, or days). You can't currently combine these to do something like "3m4s".
For output, times are printed in the local time zone as well as UTC.
Print the current time:
$ dates
now 1518150458.464 s = 2018-02-08T20:27:38.464-08:00
= 2018-02-09T04:27:38.464Z
Print an offset from the current time:
$ dates +3h
time 1 1518150462.327 s = 2018-02-08T20:27:42.327-08:00
= 2018-02-09T04:27:42.327Z
delta 10800.000 s = 0d 03h 00m 00.000s
time 2 1518161262.327 s = 2018-02-08T23:27:42.327-08:00
= 2018-02-09T07:27:42.327Z
Format a timestamp, either as a millisecond Unix time or an ISO 8601 time:
$ dates 2018-02-08
time 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
$ dates 1518048000000
time 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
$ dates 2018-02-08T21:01:23.456Z
time 1518123683.456 s = 2018-02-08T13:01:23.456-08:00
= 2018-02-08T21:01:23.456Z
You can specify the time zone, too:
$ dates 2018-02-08T13:43:00-0700
time 1518122580.000 s = 2018-02-08T12:43:00.000-08:00
= 2018-02-08T20:43:00.000Z
Subtract two times (i.e., print a delta):
$ dates 2018-02-08T00:00:00.000Z 2018-02-08T21:01:23.456Z
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
time 2 1518123683.456 s = 2018-02-08T13:01:23.456-08:00
= 2018-02-08T21:01:23.456Z
delta 75683.456 s = 0d 21h 01m 23.456s
$ dates 1518040000000 2018-02-08T00:00:00.000Z
time 1 1518040000.000 s = 2018-02-07T13:46:40.000-08:00
= 2018-02-07T21:46:40.000Z
time 2 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 8000.000 s = 0d 02h 13m 20.000s
Add a delta to a timestamp:
$ dates 2018-02-08T00:00:00.000Z +30ms
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 0.030 s = 0d 00h 00m 00.030s
time 2 1518048000.030 s = 2018-02-07T16:00:00.030-08:00
= 2018-02-08T00:00:00.030Z
$ dates 2018-02-08T00:00:00.000Z +12s
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 12.000 s = 0d 00h 00m 12.000s
time 2 1518048012.000 s = 2018-02-07T16:00:12.000-08:00
= 2018-02-08T00:00:12.000Z
$ dates 2018-02-08T00:00:00.000Z +123s
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 123.000 s = 0d 00h 02m 03.000s
time 2 1518048123.000 s = 2018-02-07T16:02:03.000-08:00
= 2018-02-08T00:02:03.000Z
$ dates 2018-02-08T00:00:00.000Z +45m
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 2700.000 s = 0d 00h 45m 00.000s
time 2 1518050700.000 s = 2018-02-07T16:45:00.000-08:00
= 2018-02-08T00:45:00.000Z
$ dates 2018-02-08T00:00:00.000Z +3h
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 10800.000 s = 0d 03h 00m 00.000s
time 2 1518058800.000 s = 2018-02-07T19:00:00.000-08:00
= 2018-02-08T03:00:00.000Z
$ dates 2018-02-08T00:00:00.000Z +7d
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta 604800.000 s = 7d 00h 00m 00.000s
time 2 1518652800.000 s = 2018-02-14T16:00:00.000-08:00
= 2018-02-15T00:00:00.000Z
$ dates 2018-02-08T00:00:00.000Z -7d
time 1 1518048000.000 s = 2018-02-07T16:00:00.000-08:00
= 2018-02-08T00:00:00.000Z
delta -604800.000 s = -7d 00h 00m 00.000s
time 2 1517443200.000 s = 2018-01-31T16:00:00.000-08:00
= 2018-02-01T00:00:00.000Z
See bin/dates.