How to set the $LANG and $LC_ALL properly

How to view the current locale setting

# locale
LANG=en_US
LC_CTYPE= "en_US"
LC_NUMERIC= "en_US"
LC_TIME= "en_US"
LC_COLLATE= "en_US"
LC_MONETARY= "en_US"
LC_MESSAGES= "en_US"
LC_ALL=en_US

How to change the locale setting

To change the current locale setting, first confirm that the desired locale is
installed on the system with:

# locale -a  en_US  en_UK  fr_FR C

If the desired locale is not in the list, you will need to install the
appropriate packages for that locale. See the Note below for more information
about locale packages.

Note: To set a default locale for a user’s environment, set the LANG or LC_*
variables in a user’s shell intialization file such as $HOME/.profile or
$HOME/.bashrc

How to change the locale by setting the system default locale

LANG=C
LC_ALL=C

Example from the /etc/default/locale file:

# Lines of this file should be of the form VAR=value, where VAR is one of
# TZ, LANG, or any of the LC_* environment variables.
LANG=C
LC_ALL=C

Note: The system must be rebooted after making changes to the /etc/default/init file in order for the changes to take effect.

How to verify the locale setting

After setting or changing the locale, verify that the locale is set correctly:

Check if the locale is set correctly by running the locale command without any
options:

# locale
LANG=C
LC_CTYPE= "C"
LC_NUMERIC= "C"
LC_TIME= "C"
LC_COLLATE= "C"
LC_MONETARY= "C"
LC_MESSAGES= "C"
LC_ALL=C