The /etc/locale.conf file configures system-wide locale settings.
The basic file format of locale.conf is a newline-separated list of environment-like shell-compatible variable assignments. It is possible to source the configuration from shell scripts, however, beyond mere variable assignments no shell features are supported, allowing applications to read the file without implementing a shell compatible execution engine.
The locale settings configured in /etc/locale.conf are system-wide and are inherited by every service or user, unless overridden or unset by individual programs or individual users. To avoid services inheriting the locale settings on sysvinit systems, the DAEMON_LOCALE variable in rc.conf can be set to "no".
In Arch /etc/rc.conf is checked for locale configuration as well, however only as fallback.
The following locale settings may be set using /etc/locale.conf: LANG=, LANGUAGE=, LC_CTYPE=, LC_NUMERIC=, LC_TIME=, LC_COLLATE=, LC_MONETARY=, LC_MESSAGES=, LC_PAPER=, LC_NAME=, LC_ADDRESS=, LC_TELEPHONE=, LC_MEASUREMENT=, LC_IDENTIFICATION=. Note that LC_ALL may not be be configured in this file. For details about the meaning and semantics of these settings, refer to locale(7). The LANG variable overrides LOCALE from /etc/rc.conf.