Getting command line parameters in Lua interpreter

Question

How can I call a function in Lua? I am new to Lua and couldn't find how to do something very simple. I write a test.lua and make it executable. Inside I put this:

function Double(n)
 return 2*n
end

print(Double(15))

If I call test.lua, it returns 30, ok.

Now I remove the print line and want to be able to call the function with something like:

test.lua 15

It doesn't work. How can I call the function from the command line or from the Lua shell without hard coding the first argument?

Answer 1

You can pass an argument to the script which will appear in the arg global.

e.g.

function Double(n)
 return 2*n
end

print(Double(arg[1]))

http://www.lua.org/pil/1.4.html