## Presentation

Siren has for main goal the mass renaming of files and folders.

Its guiding principle is the use of expressions. A rename expression describes how to build a new name. It can contain text and information specific to each treated file. The latter are used through "variables".

Here is a rapid description of a rename operation :

| Choose the directory containing the files you want to rename
| Select the files by clicking their checkboxes
| Enter a rename expression in the "Expression" text field, try : `MyFile_%n.%e` Press the "Enter" key `%n` is a variable. It represents the selection number (the value of the "Sel" column) and follows the order you have selected the files `%e` is a variable. It represents the extension of the file (for "photo.jpg" it is "jpg") The rest is fixed text that is copied as it is
| The "New name" is automatically computed
| Click on the button with the "Play" shape, the renamings are done

If you had clicked on the button with a "Fast forward" shape then instead of having renamed the files you would have copied them and named the copies after their "New name".