Deployment: Best way to switch between test and prod envs

All,

Not looking for advice on the relative wisdom of my actions :).

I have a Rails app. running under Apache 2/fastcgi that I would like to
switch from using the test environment (database) to using the
production environment (database).

I can do this by hand by modifying my xx_mod_fastcgi.conf file and
setting RAILS_ENV to be the appropriate value in the command that
initializes my dispatch.fcgi processes.

However, I’d like something a little more flexible than that so I can
switch back and forth with more ease.

Obviously, I can do a symlink thing with the mod_fastcgi.conf file, but
I was thinking, can I access OS level environment variables directly
from Apache and use their values in an Apache config file?

Like this:

FastCgiIpcDir /tmp/fcgi_ipc FastCgiServer /var/www/html/eSimplyTest/public/dispatch.fcgi \ -initial-env RAILS_ENV=${CUSTOM_ENV_VAR} \ -processes 15 -idle-timeout 300

I’d like to be able to set CUSTOM_ENV_VAR in the shell and have it be
seen by Apache.

Anybody know how to do that?

Thanks,
Wes