Ubuntu: resolve the “perl: warning: Setting locale failed” problem

Are you running Ubuntu 18.04, 20.04 or 22.04 desktop or server edition, and getting warning or errors when installing software via apt-get or aptitude?

Here is a typical error message:

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_TIME = "es_ES.UTF-8",
LC_MONETARY = "de_DE.UTF-8",
LC_ADDRESS = "de_DE.UTF-8",
LC_TELEPHONE = "de_DE.UTF-8",
LC_NAME = "de_DE.UTF-8",
LC_MEASUREMENT = "de_DE.UTF-8",
LC_IDENTIFICATION = "de_DE.UTF-8",
LC_NUMERIC = "de_DE.UTF-8",
LC_PAPER = "de_DE.UTF-8",
LANG = "en_US.UTF-8"
are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
locale: Cannot set LC_ALL to default locale: No such file or directory

Sometimes, trying to solve the problem using the update-locale or locale commands does not work and generates following error messages:

~ # sudo update-locale
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = (unset),
LC_PAPER = "de_DE.UTF-8",
LC_ADDRESS = "de_DE.UTF-8",
LC_MONETARY = "de_DE.UTF-8",
LC_NUMERIC = "de_DE.UTF-8",
LC_TELEPHONE = "en_US.UTF-8",
LC_IDENTIFICATION = "en_US.UTF-8",
LC_MEASUREMENT = "en_US.UTF-8",
LC_TIME = "es_ES.UTF-8",
LC_NAME = "de_DE.UTF-8",
LANG = (unset),
are supported and installed on your system.
perl: warning: Falling back to a fallback locale ("en_US.UTF-8").

or

~ # locale
locale: Cannot set LC_ALL to default locale: No such file or directory
LANG=en_US.UTF-8
LANGUAGE=
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=de_DE.UTF-8
LC_TIME=es_ES.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=de_DE.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=de_DE.UTF-8
LC_NAME=de_DE.UTF-8
LC_ADDRESS=de_DE.UTF-8
LC_TELEPHONE=de_DE.UTF-8
LC_MEASUREMENT=de_DE.UTF-8
LC_IDENTIFICATION=de_DE.UTF-8
LC_ALL=

Solution to the perl locale problem

The solution is to export the missing locales to ~/.bash_profile. The following command is a one-command line:

echo "export LANGUAGE=en_US.UTF-8
export LANG=en_US.UTF-8
export LC_ALL=en_US.UTF-8">>~/.bash_profile

You could also run each command separately:

echo "export LANGUAGE=en_US.UTF-8">>~/.bash_profile

Alternatively, edit ~/.bash_profile “by hand” with nano, vim or a graphical editor like gedit or xed (Linux Mint).

Don’t forget to reboot and check if the new locales are applied with the locale command.

Another solution is to add the locale variables to /etc/environment instead of ~/.bash_profile.

By Johannes Eva, April 2017 – October 2022