How to rename multiple files using bash scripting. [1/1]

This tutorial will show you how, with one raw command to rename multiple files using bash scripting.
It is written for Linux/Unix bash shell and will be useful when you want to rename files with same extension.

Here is the syntax of the string:

This line all will change all files with extension 'ext1' to 'ext2' .

The next example will convert all '.JPG' files to '.jpg' .It is really useful when you have moved files from Windows OS where the case of the extensions does not matter, but under Unix/Linux will be a problem if you are managing many files, like in galleries, photo albums etc.