major directory reorganize

sys/apps/cat.lua

@@ -0,0 +1,24 @@
+local args = { ... }
+if #args < 1 then
+  error('cat <filename>')
+end
+
+local fileName = shell.resolve(args[1])
+if not fs.exists(fileName) then
+  error('not a file: ' .. args[1])
+end
+
+local file = fs.open(fileName, 'r')
+if not file then
+  error('unable to open ' .. args[1])
+end
+
+while true do
+  local line = file.readLine()
+  if not line then
+    break
+  end
+  print(line)
+end
+
+file.close()