This code was part of the demo on creating a joomla extension http://www.slideshare.net/TimPlummer/how-to-create-a-joomla-componet-from-scratch?next_slideshow=2
It is used to rename all of the files in the helloworld example extension so that you can create a new extension from that code more quickly. In this case it creates a new extension named newthing.
@echo off
setlocal enabledelayedexpansion
for /R %%j in (*.*) do (
set filename=%%~nj
set filename=!filename:helloworld=newthing!
if not !filename!==%%~nj ren %%j
!filename!%%~xj
)
If you're continuing down the path of creating a new extension, you'll also need to do the following global search and replace.
com_helloworld = com_newthing
HelloWorld = NewThing
COM_HELLOWORLD = COM_NEWTHING
helloworld = newthing
HELLOWORLD = NEWTHING
Hello World = New Thing
hello = newthing
Hello = Newthing
World = Newthing
Consider using grepWin which is a free tool that uses grep to help with search and replace.