gistfile1.txt

1> application:set_env(tools, file_util_search_methods, bacon).
ok
2> application:ensure_all_started(tools).
{ok,[tools]}
3> application:get_all_env(tools).
[{file_util_search_methods,[{[],[]},
                            {"ebin","esrc"},
                            {"ebin","src"}]},
 {included_applications,[]}]
 
vs.

1> application:load(tools).
ok
2> application:set_env(tools, file_util_search_methods, bacon).
ok
3> application:ensure_all_started(tools).
{ok,[tools]}
4>  application:get_all_env(tools).
[{file_util_search_methods,bacon},
 {included_applications,[]}]