How rsync –compare-dest works

file-comparisonrsync

I know there's a very similar question here, but the accepted answer has nothing to do with rsync, and the OP's solution doesn't apply in my case.

I'm trying to get all the updates from a CentOS repo that differ from my local repo, by comparing them to a disk backup of the repo:

rsync -avh --dry-run --compare-dest=/run/media/user/centos6/updates/x86_64/Packages /home/REPOS/6/updates/x86_64/Packages/ updates

However, the dry-run shows that all packages will be transferred, not just the new ones.

Doing a different dry-run, as if I was copying from the repo to the disk, only transfers the new packages:

rsync -avh --dry-run /home/REPOS/6/updates/x86_64/Packages/ /run/media/djones/centos6/updates/x86_64/Packages

So rsync is clearly able to differentiate the new files, but for some reason the compare-dest option still doesn't seem to work.

The quick and dirty solution would be to simply dump a file list using the second command, and then feed that to rsync. But I'd really like to do this the "right" way.

Best Answer

I had the same trouble, you have to do:

rsync -avh --dry-run                                          \
      --compare-dest=/run/media/user/centos6/updates/x86_64/  \
      /home/REPOS/6/updates/x86_64/Packages                   \
      /path/to/updates

Note --compare-dest is the parent of Packages and do not put / at the end of source folder!

Related Solutions

Rsync – How to Delete Extraneous Files from Destination Directory

The reason your command isn't working is explained by the manual page for rsync (emphasis added):

--delete

This tells rsync to delete extraneous files from the receiving side (ones that aren’t on the sending side), but only for the directories that are being synchronized. You must have asked rsync to send the whole directory (e.g. "dir" or "dir/") without using a wildcard for the directory’s contents (e.g. "dir/*") since the wildcard is expanded by the shell and rsync thus gets a request to transfer individual files, not the files’ parent directory. Files that are excluded from the transfer are also excluded from being deleted unless you use the --delete-excluded option or mark the rules as only matching on the sending side (see the include/exclude modifiers in the FILTER RULES section).

Thus, when you run

$ rsync -d --delete SRC:{*.jpg,*.txt} DEST

the unwanted files in DEST are not being deleted because you haven't actually asked for a directory to be synced, but just for a handful of specific files. To get the results you desire, try something like this:

rsync -d --delete-excluded --include '*.jpg' --include '*.txt' --exclude '*' SRC/ DEST/

Notice that the order of the include and exclude directives matter. Essentially, each file is checked against the include or exclude patterns in the order that they appear. Thus, files with .jpg or .txt extensions are synced since they match the "included" patterns before they match the excluded "*" pattern. Everything else is excluded by the --exclude '*' pattern. The --delete-excluded option ensures that even excluded files on the DEST side are deleted.

Rsync compare directories

You will propably have to run something like rsync -avun --delete in both directions.

But what are you actually trying to accomplish?

Update:

rsync -avun --delete $TARGET $SOURCE |grep "^deleting " will give you a list of files that do not exist in the target-directory.

"grep delet" because each line prints : deleting ..file..

rsync -avun $SOURCE $TARGET will give you a list of "different" files (including new files).

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