Jq strftime() to show time in a specific time zone - jq

Question

How to use jq to convert seconds since Unix epoch to a time string in human readable format but adjusted to Sydney, Australia time zone?
I tried filter:
now | strftime("%Y-%m-%dT%H:%M:%SZ")
But I don't know how to adjust the time format string to convey Sydney, Australia time zone.
Possibly I need to replace "Z" with the relevant time zone?

Answer 1

Both of the following convert to the time zone indicated by the TZ environment variable var:
localtime | strftime(...)
strflocaltime(...)
For example,
$ jq -nr 'now | strftime("%FT%T")'
2022-02-14T06:14:07
$ jq -nr 'now | gmtime | strftime("%FT%T")'
2022-02-14T06:14:07
$ jq -nr 'now | localtime | strftime("%FT%T")'
2022-02-14T02:14:07
$ jq -nr 'now | strflocaltime("%FT%T")'
2022-02-14T02:14:07
That uses your local time, as determined by TZ environment variable. Adjust as needed.
$ TZ=America/Halifax jq -nr 'now | strflocaltime("%FT%T")'
2022-02-14T02:14:07
$ TZ=America/Toronto jq -nr 'now | strflocaltime("%FT%T")'
2022-02-14T01:14:07
$ TZ=America/Vancouver jq -nr 'now | strflocaltime("%FT%T")'
2022-02-14T22:14:07
If you want to convert to different time zones in a single run of jq, you're out of luck. jq doesn't support converting to/from time zones other than UTC and this time zone.
Tested with both 1.5 and 1.6.

Answer 2

If you are using jq v1.6, use strflocaltime instead of strftime which displays the time in your timezone.
jq -n 'now | strflocaltime("%Y-%m-%dT%H:%M:%S")'
Demo
From the manual:
The strftime(fmt) builtin formats a time (GMT) with the given format. The strflocaltime does the same, but using the local timezone setting.
If your timezone is different, set the shell's TZ variable accordingly before calling jq
TZ=Australia/Sydney jq -n 'now | strflocaltime("%Y-%m-%dT%H:%M:%S")'