i18n related settings (LANG, LANGUAGE, LC_ALL etc)

On Ubuntu, because I am using Ubuntu.

Explanation of LC_* variables

  • LANG: default locale
  • LANGUAGE: list of languages in order of preference
  • LC_ALL: overrides all other LC_* variables, for debugging

Technically the order of precedence is LANGUAGE > LC_ALL > LC_* > LANG. (According to locale(7))

Behavior on Ubuntu

This is an observation on Ubuntu 20.04, when I try to switch from Chinese (accidentally and automatically for no reason set for a newly created user) to English.

Is it in English?LANG=en_USLANGUAGE=en_USLC_ALL=en_US
Display language✅✅✅
vim messages❌✅✅
apt messages❌✅✅
welcome message*❌❌✅
sudo prompt❌❌✅

*: It's the content in /var/run/motd.dynamic that is displayed when you log in.

Bibliography