What is a locale?

Roughly speaking, the definition of regional formatting rules (currency, date, numerical representation), including language.

Locale name

Represented by language_country.character set.

Locale name	meaning
ja_JP.utf8	Japanese
en_US.utf8	English notation in the United States
en_GB.utf8	English notation in the UK
de_DE.utf8	German notation in Germany
de_H.utf8	Swiss German notation
zh_CH.utf8	Simplified characters
zh_TW.utf8	Traditional Chinese

How to check the locale

locale command

$ locale
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=

LANG environment variable

$ echo $LANG
en_US.UTF-8

locale.conf

$ cat /etc/locale.conf
en_US.UTF-8

How to set the locale

Set with environment variables

$ export LANG=ja_JP.utf8; echo $LANG
ja_JP.utf8

For CentOS

$ localectl set-locale LANG=en_US.utf8; cat /etc/locale.conf
LANG=en_US.utf8

reference

https://eng-entrance.com/linux-localization-locale https://docs.oracle.com/cd/E26924_01/html/E27144/glmbx.html

About locale