Reference:
1. http://msdn.microsoft.com/en-us/library/ms977170.aspx(前面有一段VB看不懂没关系)
2. http://csserver.evansville.edu/~amr63/linux/bash-advanced-scripting/abs-guide/dosbatch.html
3. http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/ntcmds.mspx?mfr=true
4. http://ss64.com/nt/