How to rename all the file extensions in a folder

Open a command/cmd window
navigate to the folder
type the following command
rename *.originalextension *.newextension
Example: To cange all jpg file extensions to gif extensions. You can use the following command.
rename *.jpg *.gif
Modify the values originalextension and newextension as required.
You can save this command in a batch file and execute in the respective folders.

ASP.NET usefull links in development

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http://www.devx.com/codemag/Article/20145/0/page/4
http://www.dotnetcurry.com/ShowArticle.aspx?ID=49&AspxAutoDetectCookieSupport=1