Can I list only files that exist on left side?

[SteveL]

I have used FileSync for decades in normal ways. What I need now is not quite file synching.
I now find I need to do the following:
for each file in first-dir
if file not found in second-dir then
display file name
endif
next
My attempts have been sort of successful but the work to interpret the list is staggering as only 1 in 10,000 files need attention and I have to scroll down the huge right side list looking for files with relative paths that are null.
I would like to only list files that only exist on the left disk and not anywhere on the right side.
Anyone have any thoughts on a configuration that might work?
Happy Trails

[Plerry]

You could set your FFS Synchronization Settings (F8) to Mirror or Update and try running a just a Compare (and not run the actual Sync).
Mid below the the Compare results, you can then select to only view the Category with the green left-to-right arrow with the + sign (=Category: item exists on left side only ; proposed Sync Action: copy new item to the right)and hide all other categories.
You could achieve the same by running just a Compare with a Custom Sync Setting (as opposed to Mirror or Update) with an Action Do Nothing for all Categories but the Category "Item exists on left side only", for which you select the Action copy new item to the right.

This should show all the relevant files in the FFS GUI.
If you want, you can the save the list from the FFS GUI via Tools / Export File List.

[SteveL]

That is perfect, thank you so much.
This will save me many hours of getting out my old K&R C book. I'm 69 and it's been 20 years since I wrote any code. I don't know if you are the author or a moderator but I dontated $50 for this answer.

[Plerry]

> ... I don't know if you are the author or a moderator ...
Neither of the two.
Just a very satisfied, and meanwhile relative experienced user.