Environment variables can be set in a number of ways*. However, a quick skim seems to show that in Text::ANSITable, the environment variables are simply default values for the attributes that you'd normally set via the constructor. Do you really need to do that?

* e.g. in Perl, $ENV{ENVIRONMENT_VARIABLE_NAME} = "value";, in a *NIX shell usually (depending on the shell) something like export ENVIRONMENT_VARIABLE_NAME=value or on a per command basis like ENVIRONMENT_VARIABLE_NAME=value perl script.pl