I just install BackupPC. The perl install script complains that my environment variable LANG is set to en_US.UTF-8 and that it should be en_US. This setting is specificed in RedHat 9 Linux in the file /etc/sysconfig/i18n. To check what is the current value of the LANG variable type echo $LANG. To change or set the variable to en_US type LANG=en_US
To show all environment variables, just enter
env
at the command line.
If you want to set an environment variable, you need to know what shell you are using. Many instructions still assume that you are using csh, but I guess it's maybe only 1% of Linux users that use it. E.g. in the bash shell use the following command to set the environment variable DESTDIR to /usr/local
export DESTDIR=/usr/local
while in csh type
DESTDIR = /usr/local