Turtle cmdline moving controller

-- CCTurtle 1.7
-- Turtle command line moving controller
--
-- ex:
-- turtleMove left forward left forward 2
--
-- author: nSun
-- date july-2016


local tArgs = {...}

if tArgs==nil or #tArgs<1 or tArgs[1]=="help" then
  local usage=[[Usage:
turtleMove <str:cmd> <num:rep> ...
<cmd> list:
  -Moves: forward, back, up, down
  -Rotations: left, right, uTurn
<rep>: optional
  repeat previous cmd

ex:
turtleMove left forward 2

Turtle mimic "No" on invalid commands]]
  textutils.pagedPrint(usage)
  return
end

local i,j,cmd,n,skip=1,1,"",nil,false
for i=1,#tArgs do
  if not skip then
    cmd=string.lower(tArgs[i])
    n=i<#tArgs and tonumber(tArgs[i+1]) or 1
    if cmd=="forward" then
      for j=1,n do
        if not turtle.forward() then
          return false
        end
      end
    elseif cmd=="back" then
      for j=1,n do
        if not turtle.back() then
          return false
        end
      end
    elseif cmd=="up" then
      for j=1,n do
        if not turtle.up() then
          return false
        end
      end
    elseif cmd=="down" then
      for j=1,n do
        if not turtle.down() then
          return false
        end
      end
    elseif cmd=="left" then
      for j=1,n do
        turtle.turnLeft()
      end
    elseif cmd=="right" then
      for j=1,n do
        turtle.turnRight()
      end
    elseif cmd=="uturn" then
      for j=1,n do
        turtle.turnRight()
        turtle.turnRight()
      end
    else
      for j=1,3 do
        turtle.turnLeft()
        turtle.turnRight()
      end
    end
    if n>1 then
      skip=true
      if tArgs[i+1]==nil then
        break
      end
    else
      skip=false
    end
  else
    skip=false
  end
end
return true