File: gettext.info,  Node: Locale Environment Variables,  Next: The LANGUAGE variable,  Prev: Locale Names,  Up: Setting the POSIX Locale

2.3.2 Locale Environment Variables
----------------------------------

   A locale is composed of several _locale categories_, see *note
Aspects::.  When a program looks up locale dependent values, it does
this according to the following environment variables, in priority
order:

  1. ‘LANGUAGE’
  2. ‘LC_ALL’
  3. ‘LC_xxx’, according to selected locale category: ‘LC_CTYPE’,
     ‘LC_NUMERIC’, ‘LC_TIME’, ‘LC_COLLATE’, ‘LC_MONETARY’,
     ‘LC_MESSAGES’, ...
  4. ‘LANG’

   Variables whose value is set but is empty are ignored in this lookup.

   ‘LANG’ is the normal environment variable for specifying a locale.
As a user, you normally set this variable (unless some of the other
variables have already been set by the system, in ‘/etc/profile’ or
similar initialization files).

   ‘LC_CTYPE’, ‘LC_NUMERIC’, ‘LC_TIME’, ‘LC_COLLATE’, ‘LC_MONETARY’,
‘LC_MESSAGES’, and so on, are the environment variables meant to
override ‘LANG’ and affecting a single locale category only.  For
example, assume you are a Swedish user in Spain, and you want your
programs to handle numbers and dates according to Spanish conventions,
and only the messages should be in Swedish.  Then you could create a
locale named ‘sv_ES’ or ‘sv_ES.UTF-8’ by use of the ‘localedef’ program.
But it is simpler, and achieves the same effect, to set the ‘LANG’
variable to ‘es_ES.UTF-8’ and the ‘LC_MESSAGES’ variable to
‘sv_SE.UTF-8’; these two locales come already preinstalled with the
operating system.

   ‘LC_ALL’ is an environment variable that overrides all of these.  It
is typically used in scripts that run particular programs.  For example,
‘configure’ scripts generated by GNU autoconf use ‘LC_ALL’ to make sure
that the configuration tests don't operate in locale dependent ways.

   Some systems, unfortunately, set ‘LC_ALL’ in ‘/etc/profile’ or in
similar initialization files.  As a user, you therefore have to unset
this variable if you want to set ‘LANG’ and optionally some of the other
‘LC_xxx’ variables.

   The ‘LANGUAGE’ variable is described in the next subsection.