Try to find directory containing the FreeSurfer installation, based on environment variables and *educated guessing*.
find.freesurferhome(mustWork = FALSE)logical. Whether the function should with an error stop if the directory cannot be found. If this is TRUE, the return value will be only the 'found_at' entry of the list (i.e., only the path of the FreeSurfer installation dir).
named list with the following entries: "found": logical, whether it was found. "found_at": Only set if found=TRUE, the path to the FreeSurfer installation directory (including the directory itself). See 'mustWork' for important information.