Results 2 issues of Lisa Ugray

Use common useline notation for available flags: - `[-f foo]` for (standard) optional flags - `[-f foo | -b bar]` for mutually exclusive flags - `-f foo` for required flags...

When extracting regular files, the file is opened for writing with `os.O_TRUNC`, making it suitable to extract over an existing file. This allows updating a local copy from an updated...