Problem Statement

Create a file called   "output.txt",   and place in it the contents of the file   "input.txt",   via an intermediate variable. In other words, your program will demonstrate:

Oneliners that skip the intermediate variable are of secondary interest — operating systems have copy commands for that.

Let's start with the solution:

let in  openin "input.txt"
let out openout "output.txt"
while !(catch (let c read char in))
  write c out
endwhile
close in; close out