getExecDir :: String -> IO (Maybe String)
-- (getExecDir cmd) returns the directory in which the current
-- executable, which should be called 'cmd', is running
-- So if the full path is /a/b/c/d/e, and you pass "d/e" as cmd,
-- you'll get "/a/b/c" back as the result
getExecDir :: String -> IO (Maybe String)
-- (getExecDir cmd) returns the directory in which the current
-- executable, which should be called 'cmd', is running
-- So if the full path is /a/b/c/d/e, and you pass "d/e" as cmd,
-- you'll get "/a/b/c" back as the result