立水桥梦巢酒店小姐:一个BAT脚本....谁来帮我注解一下啊?

willsort大哥在
http://zhidao.baidu.com/question/7426517.html
发出来的一个小脚本...谁来帮我解释一下每一句的意思?感激不尽啊!
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:: CompDir.cmd - Compare files in two directories.
:: Will Sort - 19:40 2005-12-23 - CMD@WinXP
@echo off & setlocal EnableDelayedExpansion
if not "%2"=="" goto Start

:Help
echo CompDir.cmd - Compare files in two directories.
echo Usage: %0 [/f] dir1 dir2 [FileSpec]
echo /f Compare time/size/attrib of file
echo filespec Specific files by wildcard of filename
goto :EOF

:Start
if /i "%1"=="/f" shift && set _CompFile=on
if "%3"=="" (set filespec=*.*) else set filespec=%3
for /r %~f1 %%f in (%filespec%) do (
set file=%%~ff
set file=!file:%~f1\=!
if not exist "%~f2\!file!" echo.Only in 1: !file!
)
for /r %~f2 %%f in (%filespec%) do (
set file=%%~ff
set file=!file:%~f2\=!
if not exist "%~f1\!file!" echo Only in 2: !file!
)
if not "%_CompFile%"=="on" goto :EOF
echo Compare Time/siZe/Attrib of file...
echo Press Ctrl+C to Quit
for /r %~f1 %%f in (%filespec%) do (
set file=%%~ff
set file=!file:%~f1\=!
if exist "%~f2\!file!" for %%g in ("%~f2\!file!") do (
if "%%~tf" NEQ "%%~tg" echo !file! Time 1"%%~zf" NEQ 2"%%~zg">>"%temp%\_CompFile.tmp"
if "%%~zf" NEQ "%%~zg" echo !file! Size 1"%%~zf" NEQ 2"%%~zg">>"%temp%\_CompFile.tmp"
if "%%~af" NEQ "%%~ag" echo !file! Attrib 1"%%~zf" NEQ 2"%%~zg">>"%temp%\_CompFile.tmp"
)
)
if exist "%temp%\_CompFile.tmp" del "%temp%\_CompFile.tmp"
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