[SOLVED] rsync syntax

Sefyir · 02-03-2017, 03:40 PM

Hello
This has always confused me and has made it difficult for me to predict rsync behavior.
I am routinely startled to discover something like this (with the subdirectory containing a full copy of the one above it, using a lot of bandwidth and space to transmit):

Code:

/foo/bar/DirectoryA/DirectoryA

What is the difference between these syntaxes?
If I plan on simply updating a directory, which one should I use?

Code:

rsync -a /foo/bar/directoryA hostname:/foo/bar/directoryA
rsync -a /foo/bar/directoryA/ hostname:/foo/bar/directoryA
rsync -a /foo/bar/directoryA hostname:/foo/bar/directoryA/
rsync -a /foo/bar/directoryA/ hostname:/foo/bar/directoryA/

astrogeek · 02-03-2017, 03:56 PM

I have wrestled with that from time to time myself.

But the man page is clear enough, if difficult to remember:

Code:

       A trailing slash on the source changes this behavior to avoid creating an additional directory level  at
       the destination.  You can think of a trailing / on a source as meaning "copy the contents of this direc‐
       tory" as opposed to "copy the directory by name", but in both cases the  attributes  of  the  containing
       directory  are  transferred to the containing directory on the destination.  In other words, each of the
       following commands copies the files in the same way,  including  their  setting  of  the  attributes  of
       /dest/foo:

              rsync -av /src/foo /dest
              rsync -av /src/foo/ /dest/foo

So the rule I have adopted which seems to work (for me) is always use trailing '/' on source, never trailing '/' on dest, and it always does what I want.

suicidaleggroll · 02-03-2017, 04:34 PM

To expand on what was written above, the trailing slash on the destination does not matter. Whether it's there or not, rsync will copy the data into said directory (similar to having a trailing slash on the source).

Doug G · 02-03-2017, 07:35 PM

I ususally use something like

Code:

rsync -a /foo/bar/directory /foo/bar/

Sefyir · 02-03-2017, 09:58 PM

Thanks, that did help clear it up.
If you want to sync directories, include the trailing slash on the source directory.

Quote:

Originally Posted by Doug G

I ususally use something like

Code:

rsync -a /foo/bar/directory /foo/bar/

I do that as well. However, it requires extra thinking to make sure it works - less you mess up and transmit the entire directory again.
I'm pretty sure most of my mess ups have been: rsync -a /foo/bar/directoryA hostname:/foo/bar/directoryA as that makes the most sense to me

So to sync /foo/bar/directoryA on local and /foo/bar/directoryA on remote, run

Code:

rsync -a /foo/bar/directoryA/ hostname:/foo/bar/directoryA

Doug G · 02-03-2017, 10:08 PM

Quote:

If you want to sync directories, include the trailing slash on the source directory.

I do just the opposite. My example above will sync /foo/bar/directory with target /foo/bar/directory.

It all has to do with how rsync matches filename patterns. I kind of saw the light (for me) when I was trying to use some exclude and include options, which never seemed to work as I expected.

Sefyir · 02-03-2017, 10:37 PM

Quote:

Originally Posted by Doug G

I do just the opposite. My example above will sync /foo/bar/directory with target /foo/bar/directory.

It all has to do with how rsync matches filename patterns. I kind of saw the light (for me) when I was trying to use some exclude and include options, which never seemed to work as I expected.

I wouldn't call it syncing, even though it has the same result in your case.

If I understand it correctly, it seems to have the behavior of:

"Copy /foo/bar to remote:/foo, if it contains a directory called bar, sync it. Otherwise copy the whole thing over."

However, what if the end directory is different?
Eg.
How do you sync local dir /foo/bar/directoryA and remote dir /foo/bar/directoryB?

rsync -a /foo/bar/directoryA/ remote:/foo/bar/directoryB will have the expected result, directoryA and directoryB contain the same content.
But if you do rsync -a /foo/bar/directoryA remote:/foo/bar/directoryB DirectoryB will contain DirectoryB/DirectoryA!
And by doing rsync -a /foo/bar/directoryA remote:/foo/bar, you end up with /foo/bar/directoryA. Something you may not want or expect

I'm glad I created this thread, it is clearing up the behavior of rsync greatly for me!

Doug G · 02-04-2017, 11:50 PM

Quote:

I'm glad I created this thread, it is clearing up the behavior of rsync greatly for me!

Me too. I always feel like the creators of rsync made a superior product but almost intentionally made it difficult to do some pretty simple tasks. Once you spend all the hours of research, rsync performs excellently. Just my $0.00000000002