> Why would anyone want environment variables when you can have config files or explicit options instead? If you have an underlying .so used by an application

> Why would anyone want environment variables when you can have config files or explicit options instead? If you have an underlying .so used by an application that hasn't implemented optioning at init of said library it can then let you control things in something that has no runtime configuration source. I've written several such libraries. Also good for controlling things you override with LD_PRELOAD