Locales is a set of environment variables that are used to determine how to display data and time (for example, first of the week), symbols encoding (for example, how to display cyrillic symbols), default files order when one executing the ls command, and so on.
Those variables are:
LANG: Determines the default locale in the absence of other locale related environment variables
LANGUAGE: List of fallback message translation languages
LC_CTYPE: Character classification and case conversion
LC_NUMERIC: Numeric formatting
LC_TIME: Date and time formats
LC_COLLATE: Collation (sort) order
LC_MONETARY: Monetary formatting
LC_MESSAGES: Format of interactive words and responses
LC_PAPER: Default paper size for region
LC_NAME: Name formats
LC_ADDRESS: Convention used for formatting of street or postal addresses
LC_TELEPHONE: Conventions used for representation of telephone numbers
LC_MEASUREMENT: Default measurement system used within the region
LC_IDENTIFICATION: Metadata about the locale information
LC_RESPONSE: Determines how responses (such as Yes and No) appear in the local language (not in use by Debian GNU/Linux but Ubuntu)
LC_ALL: Overrides all other locale variables (except LANGUAGE)
Contents
Locale and Cyrillic symbols
For example, when running a vifm tool in the KDE Konsole on my Arch Linux – cyrillic symbols are not displayed correctly:
And after exiting from the vifm terminal produces an error message:
Locales are described in a corresponding file in the /usr/share/i18n/locales/ catalog which is used during locale-gen. For example, for the en_US its LC_TIME locale is described as:
LC_TIME
abday "Sun";"Mon";"Tue";"Wed";"Thu";"Fri";"Sat"
day "Sunday";/
"Monday";/
"Tuesday";/
"Wednesday";/
"Thursday";/
"Friday";/
"Saturday"
week 7;19971130;1
abmon "Jan";"Feb";/
"Mar";"Apr";/
"May";"Jun";/
"Jul";"Aug";/
"Sep";"Oct";/
"Nov";"Dec"
mon "January";/
"February";/
"March";/
"April";/
"May";/
"June";/
"July";/
"August";/
"September";/
"October";/
"November";/
"December"
% Appropriate date and time representation (%c)
d_t_fmt "%a %d %b %Y %r %Z"
%
% Appropriate date representation (%x)
d_fmt "%m//%d//%Y"
%
% Appropriate time representation (%X)
t_fmt "%r"
%
% Appropriate AM/PM time representation (%r)
t_fmt_ampm "%I:%M:%S %p"
%
% Appropriate date and time representation for date(1). This is
% different from d_t_fmt for historical reasons and has been different
% since 2000 when date_fmt was added as a GNU extension. At the end
% of 2018 it was adjusted to use 12H time (bug 24046) instead of 24H.
date_fmt "%a %b %e %r %Z %Y"
%
% Strings for AM/PM
%
am_pm "AM";"PM"
END LC_TIME
And for the ru_RU its LC_TIME has the first_weekday option set, see man 5 locale, which specifies the first day of the week – Monday (which is second in the list):
...
week 7;19971130;1
first_weekday 2
END LC_TIME
...
To set Monday as the first day of the week, set the LC_TIME as ru_RU.UTF-8 in the /etc/locale.conf file. At first, uncomment it in the /etc/locale.gen and then execute the locale-gen: