r"""Usage:
  prog [-a] command
  prog [-a]

"""
$ prog
{"-a": false, "command": false}

$ prog -b
"user-error"

$ prog -a
{"-a": true, "command": false}

$ prog -a command
{"-a": true, "command": true}

$ prog command
{"-a": false, "command": true}


r"""Usage:
  prog [-o OPT]

Options: -o OPT  Option [default: \$var]
"""
$ prog
{"-o": "$var"}


r"""Usage:
  prog [-o OPT]

Options: -o OPT  Option [default: \"]
"""
$ prog
{"-o": "\""}

