Alphanumeric

The Alphanumeric tab allows you to replace the names of the listed or selected files with a Numerical (e.g. 1, 2, 3, 4, 11, 12, etc.), Alphabetical (e.g. A, B, C, D, AA, AB, etc.) sequence.

The file extensions remain unchanged. Each kind of sequence is limited to a Range of single digit values that is set on the Settings Dialog Box. As the files are renamed in the order in which they appear, the last digit cycles through the Range, adding and cycling through a 'tens' and 'hundreds' digit as needed, just as you would expect in any counter (only here, the base value can be anything you choose).

You can start with any valid value and Increment/Decrement by any valid value.

If you enter one or more characters into the Padding Mask, characters from the mask are used to fill out the file name to the left of the sequence (most typically, with leading zeros). So, for example, a Padding Mask of "0000" will fill out "1" to "0001" and a Padding Mask of "____" will fill out "BG" to "__BG". The Padding Mask does not need to be a valid value in the selected Range, as long as it consists of valid file name characters. The length of the Padding Mask automatically limits the length of the Start and Increment/Decrement values, but you should still be careful not to set these values so that the file names run out of room later on in the sequence.

Technically you can create alphabetic and Numeric string with these setting. Now you can add this new string with original file name as Prefix or Suffix with separator. If you do not check Prefix or Suffix check box then files would get new name without using original file name. You can also add separator between new counter sequence and original file name.

You can rename files in alphabetic and numeric sequence in sub folder with recursive renaming with all files in sub folder. Please understand how sequence counter works in sub folder. See here.