I appear to be having a problem in DOpus 9.1 with using the 'Skip Identical' option of the file copy dialog.
The attached screenshot shows that I'm copying a file to replace another file of the same name. They are different in size and have different file dates. And yet, if I select Skip Identical, the copy is not made.
Skip Identical tells Opus not to prompt you when it encounters "identical" files, skipping them automatically instead.
("Identical" here is defined as the same name, date and size. Contents aren't compared.)
Since those two files are not identical, clicking on Skip Identical won't have any effect on them. (It will still prevent other files that are about to be copied from triggering prompts if they are identical, though.)
If you want to skip all files that have the same name, whether or not they have the same date and size, then you should use the Skip All option instead.
My point being that the files aren't identical, and yet no copy was made. Just so I'm clear, given the details being shown in the dialog, what would you have expected to happen if you'd clicked on 'Skip Identical'? I expected the file to be copied, because the two files aren't identical (they have the same name, but don't have the same date or size). Do I have that wrong?
[quote="jon"]'Skip Identical' always skips the current file, and then auto-skips any 'identical' files that come later.
The button would be more accurately labelled "Skip this file, and then skip any subsequent identical files", but that doesn't fit [/quote]
I'm sure this makes sense to others, but it makes no sense to me at all.
If I were copying 1 file or 100 files, I would have previously very strongly expected 'Skip Identical' to compare each file being copied from directory A into directory B to see if an 'identical file' already exists in directory B and to skip copying of each file where an identical file already exists.
So, it really surprised me that the file in my example wasn't copied, because the files definitely weren't identical.
Even if the label were renamed (ie you had unlimited screen real estate and your sense of aesthetics was terminally impaired), I wouldn't understand why always skipping the first file would be the desired behaviour -- after all, the dialog is telling me there's a potential clash, and 'Skip Identical' is what I want to do about that clash.
None of this, by the way, is intended as criticism.
Skip Identical won't cause anything to be copied. It'll only cause things to be skipped. When Opus comes across a file that isn't identical it will ask you what you want to do.
Skip Identical is purely about preventing you from being prompted about lots of files, so that you only have to make choices for the files that aren't identical.
Opus knows you want to skip the identical files but, until you tell it, it doesn't know what to do when two files are different. You may want to skip identical and replace all, or keep both versions and rename the new files (or the old files), or do something different for each file.
So you can Skip Identical, and the next time you are prompted you can Replace All, and then I think you'll get what you want.
The only problem is that since Skip Identical always skips the current file, as Jon mentions, you cannot choose it until you actually get an identical file, else you'll skip one you wanted to copy. So you might have to click Replace a few times until you get the chance to Skip Identical, which isn't ideal.
Perhaps Skip Identical should be a checkbox in the dialog, allowing you to turn it on and, at the same time, choose one of the other options the first time the dialog appears. Opus would then skip the current file if, and only if, it was identical and apply whatever button you clicked otherwise (and do the same to the rest of the files).
("Identical" above always meaning same name, date and size. I suspect that if Opus compared the actual contents of files to avoid copying data that's the same then it would usually end up slower than blindly overwriting everything, although there is something to be said for comparing the contents when you've set Opus to keep both files, I suppose.)
A simpler solution is just to disable the button (it's just one simple Windows API call) if the current file is not identical. Opus already has the file info for both files, so there would be pretty much no additional overhead whatsoever.
This conversation has been really interesting to me. I'm still not sure I have any place in my life for the way Skip Identical works, which is a shame, because I like to feel that I am getting the most out of a product as excellent as DOpus.
I still wish Skip Identical behaved the way I thought it did. Where I'm copying very large files, I can really see the point in 'Copy these files, and if any of them are identical, skip them to save yourself some time.'
I think that the sensible thing is to offer the button still anyway... like planetT suggested, the fact that a confirmation dialog has popped up at all and offers the user a choice on how to handle all subsequent conflicts is a GOOD thing...
But simply put, the 'Skip Identical' selection should certainly APPLY the rules of what makes a file Identical TO the current file... (whatever those rules might be - and Nudel is totally right about doing byte-for-byte comparisons during 'regular' copy operations - this is way too much overhead and why there are other facilities in Opus which do this outside of standard 'copy' command). Otherwise, why would a user ever want to skip files 'only' when they're identical ~except~ for the first non-identical file that causes the dialog to appear... we'll just skip that file as well for good measure? LOL - pretty funny logic...
Either way... it's a good case for a general 'skipidentical' argument to the copy command which I think has come up recently... or see if the existing UPDATExxx related copy args do the same effective thing (though I think they're a bit different).
[quote="steje"]I think that the sensible thing is to offer the button still anyway... like planetT suggested, the fact that a confirmation dialog has popped up at all and offers the user a choice on how to handle all subsequent conflicts is a GOOD thing...
But simply put, the 'Skip Identical' selection should certainly APPLY the rules of what makes a file Identical TO the current file...[/quote]
I think this is the central issue to me. My logic is, "I've initiated a copy, I've been told there's a potential clash, I'd like to skip the copy if the files are identical."
In a way, I think I understand to some extent the reasoning why this doesn't currently happen, because I'm assuming Skip Identical still prompts with a dialogue when a non-identical file exists in the target directory with the same name.
I guess I'm looking, then, for an operation that is more "Copy Without Identical", where I want the copy to be made if the same file name exists but the details are different, but I don't want time lost copying large files that do already exist in the target directory.