Total Commander for Android : multi rename tool

Source

After breaking my head for an hour figured it out and it turns out to be quite simple!(see source)

From my call recorder files in mp3 format, I picked up two records and changed the file name to conceal identity/number in the file name . I wanted to convert them to jpg files with only the first five letters in file name.

That is

nonsense name 914850098765678902345.mp3 → nonse.jpg

abracadabra 2021-09-24 14.19.44_O_P330.mp3 → abrac.jpg

All you need to do is to enter [N1-5] in the name mask, which means retain first five characters in the file name and enter the desired extension. Nothing else.

Click START! and you are done!

Here are the changes in the folder for these two files

You can also undo the changes by selecting the changed files, going to Multi-rename tool and ... → undo last operation. If you need to do these operations frequently, from the 3 dots options save as a profile and use that profile to save yourself the bother of setting it up again.