>>> import shlex, subprocess

>>> command_line = raw_input()

/bin/vikings -input eggs.txt -output "spam spam.txt" -cmd "echo '$MONEY'"

>>> args = shlex.split(command_line)

>>> print args

['/bin/vikings', '-input', 'eggs.txt', '-output', 'spam spam.txt', '-cmd', "echo '$MONEY'"]

>>> p = subprocess.Popen(args) # Success!