Handling Multiple Command-Line Options

As we’ve seen while implementing the initial version of our command-line interface, using the os.Args variable isn’t a flexible way of handling command-line arguments. Let’s improve the tool by using the flag package to parse and handle multiple command-line options.

Command-line flags

The flag package enables us to define command-line flags of specific types such as int or string, so we don’t need to convert them manually. This version of the tool will accept three command-line arguments:

• -list: A boolean flag. When used, the tool will list all to-do items.
• -task: A string flag. When used, the tool will include the string argument as a new to-do item in the list.
• -complete: An integer flag. When used, the tool will mark the item number as completed.