How to change locale environment variable?

  • I have generated en_US.utf8, et_EE.iso88591 and ru_RU.utf8 localisation files. Now if I try to change any of the locale variables to a ru_RU.utf8 or en_US.utf8, then this does not have any effect:

    # locale -a
    C
    en_US.utf8
    et_EE
    et_EE.iso88591
    POSIX
    ru_RU.utf8
    # LC_TIME=ru_RU.utf8
    # locale | grep LC_TIME
    LC_TIME="et_EE.iso88591"
    # LC_TIME="ru_RU.utf8"
    # locale | grep LC_TIME
    LC_TIME="et_EE.iso88591"
    # 
    

    However, if I change the LANG= variable, then all other variables but LANGUAGE= and LC_ALL= take the value of the LANG= variable. Is there a way to modify each locale variable separately? In addition, am I correct that locale variables aren't regular shell variables, but more like parameters to locale utility?

  • You can set any locale category independently. LANG applies only to the categories that are not explicitly set.

    LANG and LC_xxx are ordinary environment variables. They are not settings for the locale utility: the locale program isn't involved in any locale processing, it's just a small utility to report current and available locale settings.

    When you write LC_TIME=ru_RU.utf8, this doesn't set an environment variable, only a shell variable. Shell variables are internal to the shell, they are not seen by other programs. Environment variables, on the other hand, are inherited by the programs that the shell starts. You need to export the variable to the environment as well:

    $ LC_TIME=ru_RU.utf8
    $ locale | grep LC_TIME
    LC_TIME="et_EE.iso88591"
    $ export LC_TIME
    $ locale | grep LC_TIME
    LC_TIME="ru_RU.utf8"
    

    or directly

    $ export LC_TIME=ru_RU.utf8
    $ locale | grep LC_TIME
    LC_TIME="ru_RU.utf8"
    

    *"LANG and LC_xxx are ordinary environment variables"* How do you know that `LANG` and `LC_xxx` are environment variables? my testing shows that only `LANG` and `LANGUAGE` and `LC_MESSAGES` and `LC_ALL` are environment variables, while other variables like `LC_CTYPE` and `LC_MONETARY` are not environment variables (also, they are not shell variables)?

    @rony_t You can look at the source code of applications and libraries, look at their documentation, or experiment with them. For example, compate `env LC_TIME=en_GB date` with `env LC_TIME=fr_FR date` and `env PATH="$PATH" date` (obviously, pick locales that exist on your system). Obviously, each variable may or may not be set in a given process's environment. What testing did you do? Are you sure the application you used behaves differently based on `LC_CTYPE` (fairly common) and `LC_MONETARY` (pretty rare)?

    In the terminal, I executed the `printenv` command to list the environment variables of bash, and only `LANG` and `LANGUAGE` and `LC_MESSAGES` and `LC_ALL` were listed as environment variables. I also executed the command `set -o posix` followed by the command `set` to get the environment variables and the shell variables of bash, and only `LANG` and `LANGUAGE` and `LC_MESSAGES` and `LC_ALL` were listed. So this means that `LANG` and `LANGUAGE` and `LC_MESSAGES` and `LC_ALL` are environment variables and the rest of the locale variables are not, and also they are not shell variables.

    @rony_t No. It means that _you_ have set the environment variables `LANG`, `LANGUAGE`, `LC_MESSAGES` and `LC_ALL`. (Either you did this explicitly or your distribution or your system administrator did it for you.) You can set an environment variable by any (syntactically valid) name! But some names are meaningful to some application, and some names aren't. `LC_MESSAGES`, `LC_CTYPE`, `LC_TIME` and so on are used by applications that care about the language of error messages, the character encoding, the time format, and so on.

    @rony_t By the way your configuration is very strange. The setting of `LC_ALL` overrides all the other settings, so the value of the other locale variables doesn't matter. It's normally only used temporarily to force a program to use a given locale, it doesn't make sense to have it in your normal environment.

    You are right, it depends on the distribution. The locale environment variables on Knoppix are different from the locale environment variables on Lubuntu. And `LC_ALL` is only set on Knoppix and not on Lubuntu.

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Content dated before 6/26/2020 9:53 AM