Custom locale to use ISO 8601 date format

[andrew clarke]

Here in Australia the general population uses the British DD/MM/YY
format for representing dates, eg. today is 07/06/15, and the
en_AU.UTF-8 locale in FreeBSD 10.1 honours that:

lrwxr-xr-x  1 root  wheel  22 17 Feb  2011 /usr/share/locale/en_AU.UTF-8/LC_TIME -> ../en_GB.UTF-8/LC_TIME

However I wanted programs to use the ISO 8601 YYYY-MM-DD date format
(2015-06-07) instead. To do this in Linux, the general method seems to
set LC_TIME=en_DK.utf8, but FreeBSD has no locale by that name.

As root, I could modify /usr/share/locale/en_AU.UTF-8/LC_TIME, but
that could be overwritten when I upgrade to 10.2 with freebsd-update.

After reading locale(1) it turns out users can set
PATH_LOCALE=$HOME/locale to use their own custom locales, so I copied
/usr/share/locale/ to $HOME/locale/ then modified
$HOME/locale/en_AU.UTF-8/LC_TIME:

$ diff -u /usr/share/locale/en_AU.UTF-8/LC_TIME $HOME/locale/en_AU.UTF-8/LC_TIME
--- /usr/share/locale/en_AU.UTF-8/LC_TIME       2011-02-17 13:19:18.000000000 +1100
+++ /home/ozzmosis/locale/en_AU.UTF-8/LC_TIME   2015-06-07 18:17:57.537156884 +1000
@@ -37,7 +37,7 @@
 Friday
 Saturday
 %H:%M:%S
-%d/%m/%Y
+%Y-%m-%d
 %a %e %b %X %Y
 am
 pm

Make sure LANG=en_AU.UTF-8 is set in your login, then logout and back in:

$ locale
LANG=en_AU.UTF-8
LC_CTYPE="en_AU.UTF-8"
LC_COLLATE="en_AU.UTF-8"
LC_TIME="en_AU.UTF-8"
LC_NUMERIC="en_AU.UTF-8"
LC_MONETARY="en_AU.UTF-8"
LC_MESSAGES="en_AU.UTF-8"
LC_ALL=

$ date +"%x %X"
2015-06-07 18:42:59

Hopefully others find this useful.

Regards
Andrew