I forgot you have to give it write permissions (minified)

halyde/apps/cp.lua

@@ -1,26 +1 @@
-local fromFile, toFile = ...
-local fs = import("filesystem")
-
-if not fromFile or not toFile then
-  shell.run("help cp")
-  return
-end
-if fromFile:sub(1, 1) ~= "/" then
-  fromFile = fs.concat(shell.workingDirectory, fromFile)
-end
-if toFile:sub(1, 1) ~= "/" then
-  toFile = fs.concat(shell.workingDirectory, toFile)
-end
-if fromFile == toFile then
-  print("\27[91mSource and destination are the same.")
-  return
-end
-if not fs.exists(fromFile) then
-  print("\27[91mSource file does not exist.")
-  return
-end
-if fs.exists(toFile) and not (table.find({...}, "-o") or table.find({...}, "--overwrite")) then
-  print("\27[91mDestination file already exists. Run this command again with -o to overwrite it.")
-  return
-end
-fs.copy(fromFile, toFile)
+Error: no such file. (``)