When invoked without arguments, locale summarizes the current locale environment for each locale category defined by the LC_* environment variables.
-a, --all-locales
        Write names of available locales.
-m, --charmaps
        Write names of available charmaps.
Output Format:
        Write names of selected categories.
-k, --keyword-name
        Write names and values of selected keywords.
 
LC_CTYPE
        Character classification and case conversion.
LC_COLLATE
        Collation order.
LC_TIME
        Date and time formats.
LC_NUMERIC
        Non-monetary numeric formats.
LC_MONETARY
        Monetary formats.
LC_MESSAGES
        Formats of informative and diagnostic messages and
        interactive responses.
LC_PAPER
        Paper size.
LC_NAME
        Name formats.
LC_ADDRESS
        Address formats and location information.
LC_TELEPHONE
        Telephone number formats.
LC_MEASUREMENT
        Measurement units (Metric or Other).
LC_IDENTIFICATION
        Metadata about the locale information.
This environment variable can switch against multiple locale database:
LOCPATH
        The directory where locale data is stored.  By default, /usr/lib/locale is used.
This manpage was written by Joel Klecker <espy@debian.org> for the Debian GNU/Linux system, and expanded by Alastair McKinstry <mckinstry@computer.org>