How to add an extension to a file name (automate)?

Question

Automation

There is a folder with subfolders. Within subfolders, there are files with .jpg extension and files without extension.
It is necessary to add the extension .jpg to files without extension.
Please tell me how you can automate / optimize this procedure without opening each folder.

Answer 1

TotalCommander has a very good batch rename utility, and an equally good search that can be renamed.

Answer 2

PowerShell.

Answer 3

You can add to all: file.jpg.jpg will still remain jpg.
forfiles /?

Answer 4

Run powershell and paste this command
This command will write those renames that it will implement. Recursively starting from the current folder. If the result suits you, you need to remove -WhatIf and run it again. She will rename