I took it as to prevent copying the same files with different names.

Hi 1in10,

I am going to address just your initial follow up post after my suggestion in post #2, since you appear to be a moving target.

This happens because xargs does not like to receive arguments in the input stream if they contain a single unmatched quote. Apparently, some of your songs have apostrophe in their file names.

The meaning of this error is that cp cannot find a song named "World Party - Goodbye Jumbo - 05 - Aint Gonna Come Till Im Ready.mp3" in the directory /home/directory/orgin/transit to copy.

Go manually there and check if that file exist as is reported by the error.
Pay attention if Aint has an apostrophe in the real file as Ain't . If it does, then after passing through all the piping the apostrophe is being removed.

To address the issue of the apostrophe, I am not quite sure if any of the following techniques might help, but you may try:

Code:

find /home/directory/origin -type f -iname "*.mp3" -exec sha256sum {} \+ |
 sort -u -k1,1 | cut -c 67- | tr \\n \\0 | xargs -0 -I{} cp {} /home/directory/destination

The command tr will switch any newline for a NULL and then I am telling xargs to separate the arguments by NULL, doing this in my version, it does ignore the apostrophe and it let it be alone. I am following the suggestion given by the original error: or

Code:

find /home/directory/origin -type f -iname "*.mp3" -exec sha256sum {} \+ |
sort -u -k1,1 | cut -c 67- | sed "s/'/\\\'/g"  | xargs -I{} cp {} /home/directory/destination

In this version, sed is escaping any apostrophes; by the time xargs sees the stream they are protected by a `\' and treated correctly. That's the hope.

This could happen if the whole process stopped prematurely, or if sha256sum tagged those files with the same hash, which sort -u would have removed from the stream passed to xargs.

You can troubleshoot that by just running part of the command up to sha256sum and checking manually what's being done there.

Code:

find /home/directory/origin -type f -iname "*.mp3" -exec sha256sum {} \+

Check the hash of some of those file that you consider missing.