Really Basic Automator Rename Help Please

Here is another approach to using Automator in processing custom filenames as you have shared. It can handle multiple selections of files and folders, and process your image pattern rename in each file encountered. It is extended for other image formats than jpg, and if you have RAW files, you can add those as lower case extensions too.

Run shell script code:

: <<'COMMENT'
Given files and folders as input, convert filenames from imagenn_vnn.ext to imagenn_RGB.ext.
If encountering a folder, then process all image files in its first level w/o recursion.
COMMENT

autoload -U zmv

function rename_file () {

	# rename imagenn_Vnn.jpg to imagenn_RGB.jpg using zmv pattern.
	zmv ${1} ${f//_[Vv][0-9]*/_RGB.${2}}
	return
}

function rename_folder_contents () {
	# case insensitive search of images in the folder.
	setopt NO_CASE_GLOB
	for f in ${1:a}/*.(jpg|jpeg|png|tif|tiff)(.N);
	do
		$(rename_file "${f}" "${f:e}")
	done
	return
}

for f in "$@";
do
	# is this a folder or a file?
	# pass folder to its function, filename and extension to its function
	if [[ -d "${f:a}" ]]; then
		rename_folder_contents "${f:a}"
	else
		rename_file "${f:a}" "${f:e}"
	fi
done
exit 0

Tested with Automator on macOS 11.6.6 and Zsh shell v5.8.

Without seeing your workflow it's impossible to predict what's not working, or what changes might need to be made.

Additionally, as described, the script is doomed to fail if there are multiple Vx files passed in.

For example, if you have image_V1.jpg, image_V2.jpg and image_V3.jpg, your workflow should change image_V1.jpg to image_RGB.jpg - fair enough. But the file image_V2.jpg should then also be renamed to image_RGB.jpg. Should that replace the existing file? fail gracefully? ask the user? etc.?

Ultimately, though, Automator is great at linear tasks. It's less suited to workflows that require looping or logic filters. Not to say it can't be done, but it takes more effort.

The reason why the workflow only processes the _V1 files is a perfect example of how/why Automator fails when there's any kind of logic processing or iteration.

To explain, your first step renames items that have _V1 in their name. That's fine, and what you what.

HOWEVER, the OUTPUT of this command (in short, a list of the files that were renamed) are then passed in to step 2.

To be clear, NONE of these file names will contain _V2 because this is a list of the files that were renamed from _V1 to _RGB

You see, the issue is that that output of one step is passed as the input to the next step.

What you need is for *each* of the steps to process the full list of files. That adds a degree of complexity.

In this case it probably hinges around taking the input list of files and storing that in a variable (via a 'Set value of variable' action). Then your workflow becomes a series of 'Get value of Variable' passed into a 'Rename Finder Items' action.

Now each rename will act on the full list of files, rather than the list of files that were just renamed.

Alternatively, as Viking shows, extracting the logic part to a shell script (or an AppleScript) avoids having to play such games.

You are welcome.