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Given folders named Drive1/Folder1 and /Drive2/Folder2 I want to have a folder /Drive3/folder3 that contains the synced merged contents of both the source folders, but does not contain any files or directories that have been removed from the source folders.

/Drive1/Dolder1/File1
                File2
/Drive2/Folder2/File6
                File7
                File8
/Drive3/Folder1/File1
                File2
                File6
                File7

When File7 is deleted, the next sync removes it from the target Drive3 directory while leaving all the other files behind.

The only solution I can think of that could work is to create a /tmp/folder3 folder and then make hard links in that folder and rsync that folder with --delete, but that won’t work because /Drive1 an /Drive2 are not the same volume.

I thought I could do this with rsync. but everything I try either removes all of the Drive1 files or the Drive2 files each time.

lbutlr
  • 123

1 Answers1

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The following will work for files that don't contain newlines in their names

Example

mkdir -p {Drive1/Folder1,Drive2/Folder2,Drive3/Folder}
touch Drive1/Folder1/File{1,2} Drive2/Folder2/File{6,7,8}

Copy files from Drive1


rsync -av Drive1/Folder1/ Drive3/Folder/


Copy files from Drive2


rsync -av Drive2/Folder2/ Drive3/Folder/


Generate file lists


( cd Drive1/Folder1 && find -type f ) >d1f1
( cd Drive2/Folder2 && find -type f ) >d2f2
( cd Drive3/FolderM && find -type f ) | LC_ALL=C sort >d3f


Compare them to get the list of files to delete from the destination (optional)


Delete the list of files


comm -13 <(LC_ALL=C sort d1f1 d2f2) d3f |
    while IFS= read -r file
    do
        echo "Deleting $file" >&2
        rm -f "Drive3/Folder/$file"
    done


Tidy up


rm -f d1f1 d2f2 d3f
Chris Davies
  • 4,560