I’m afraid that doesn’t do anything here, even if I’m already in the subdirectory where the files to be renamed reside. I’ve tried it both ways (in parent directory, and in directory with files) via custom command from menu, and via > directly in lister. Nothing. But I really want to target only the contents of the specific subdirectory (or subdirectories) corresponding to the selected files anyway. Apart from the lingering mystery of why neither your method nor any of the previous ones I tried worked, I did end up getting the following to do what I wanted, based on help from lxp in the thread “Rename PATTERN TO REGEXP with filename-passing codes” that I started last July (thanks again, @lxp!):
Rename FROM="{filepath$}.parts\*" PATTERN="({file$}\.part\.\d{5})" TO="\1.txt" REGEXP