converting .001 .002 file

I have a folder of several hundred files with extensions .001 .002 etc How can I rename them such that I retain the detail in the extension but convert them to a more usable file format such as .m file or .txt

So an example of the current filenames:

PUVT0000.000

PUVT0000.001

PUVT0000.002

PUVT0000.003

PUVT0001.002

PUVT0001.004

PUVT0001.005

PUVT0002.004

and what the desired filename:

PUVT0000_000.txt

PUVT0000_001.txt

PUVT0000_002.txt

PUVT0000_003.txt

PUVT0001_002.txt etc.

Answer 1

[KSSV]

http://in.mathworks.com/matlabcentral/answers/314319-how-to-rename-a-lot-of-files

[Dom Smith]

Thank you, but I need to keep the information in the extension somehow as it provides the sequential information I need that isn't in the root

[Walter Roberson]

If you look at that solution, KSSV included a line

      [~, f] = fileparts(files(id).name);

fileparts() can also have a third output, which is the file extension. You can create a new name from f and the file extension:

      orig_name = files(id).name;
      [~, basename, ext] = fileparts(orig_name);
      new_name = [basename '_', ext(2:end) '.txt'];
      movefile(orig_name, new_name);

[Dom Smith]

Ahh legend, thank you both very much

Answer 2

[John D'Errico]

Get a list of all the files. dir will do that.

help dir

Then, rename each file, using a loop over the files. Just create the new name in each case from the old, as a string. WTP?