batch-file cmd error-handling copy stderr

COPY command - unexpected results in STDERR redirection inside a .BAT file

I am trying to log each file transfer using COPY command and the redirect STDERR handle in the following .BAT file:

Copy /Y FileExist01.txt NewFile01.txt 2>CopyError.log
Copy /Y NoFile02.txt NewFile02.txt 2>>CopyError.log
Copy /Y FileExist03.txt NewFile03.txt 2>>CopyError.log
Copy /Y NoFile04.txt NewFile04.txt 2>>CopyError.log

FileExist##.txt are files that I know exist (verified path and
filename)
NoFile##.txt are files that I know do not exist to test the STDERR redirect on error (2>>CopyError.log)

I was expecting to see 2 error lines in the CopyError.log to show "The system cannot find the path specified." but instead CopyError.log is empty.

Solution

Unfortunately, Copy doesn't output that message as StdErr.

Previously XCopy was offered as an alternative. See this question for more information, however here's a quick idea for you:

(   Copy /Y "FileExist01.txt" "NewFile01.txt"
    Copy /Y "NoFile02.txt" "NewFile02.txt"
    Copy /Y "FileExist03.txt" "NewFile03.txt"
    Copy /Y "NoFile04.txt" "NewFile04.txt"
)|FindStr /VRC:"^ ">"CopyError.log"

Now, as with your intended method, this will not tell you which of the commands actually output the message. If you wanted to do that, you could, I suppose, output the line number:

(   Copy /Y "FileExist01.txt" "NewFile01.txt"
    Copy /Y "NoFile02.txt" "NewFile02.txt"
    Copy /Y "FileExist03.txt" "NewFile03.txt"
    Copy /Y "NoFile04.txt" "NewFile04.txt"
)|FindStr /VRNC:"^ ">"CopyError.log"

Here, the error should be prepended with the number, in this case:

2:The system cannot find the file specified.
4:The system cannot find the file specified.

You will at least then be able to see that it was your 2nd and 4th copy commands which failed.