What does 'sys.argv' mean?

Question

I am learning from code, and I am get confused by one of its lines which is:

things = [float(arg) for arg in sys.argv[1:]]
Omega_a, Omega_b, Delta_a, Delta_b         


        

Answer 1

Parameters aren't the same as program input. For example, here's wget used with parameters:

$ wget "I am a parameter!"

Here's cat used with input:

$ cat
Now you type. This is the input.

That's the reason for your error, too - you can't specify the parameters as such after you run the program.