[Freeswitch-users] Variables for install directories

Searching through the wiki for any indication as to what if any variables exist for the install location in that I can leverage in a script. Can anyone point me along, I can't seem to find anything. I want to place a shell script in /opt/freeswitch/scripts that needs a reference to a conf file that a binary it runs is calling. So now I have in two places hardcoded paths that I was hoping to avoid, in the dialplan and in the shell script. When either of these is run, does there exist something like <action application="system" data=${freeswitch_install_dir}/scripts/shell_script.sh"/> and the same for use inside the shell script? Thanks! jlc