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:

inout:=proc(filename)
local f;
f:=FileTools[Text][ReadFile](filename);
FileTools[Text][WriteFile]("output.txt",f);
end proc;