Lately I've written all my tools to not only announce where they're reading their configs from (which isn't precisely what OP is asking for but is close), but a

Lately I've written all my tools to not only announce where they're reading their configs from (which isn't precisely what OP is asking for but is close), but also to have an option to generate the default config that will be presumed if a config file is not found. "mytool --gen-config /tmp/newconfig.txt" should produce a fully-formed config with all defaults explicitly set which can be moved into /etc/mytool.conf or wherever it's supposed to go, all ready for me to tweak without having to look up settings names.