What does f+++++++++ mean in rsync logs?

I'm using rsync to make a backup of my server files, and I have two questions:

1. In the middle of the process I need to stop and start rsync again.
   Will rsync start from the point where it stopped or it will restart from the beginning?

2. In the log files I see "f+++++++++". What does it mean?

e.g.:

2010/12/21 08:28:37 [4537] >f.st...... iddd/logs/website-production-access_log
2010/12/21 08:29:11 [4537] >f.st...... iddd/web/website/production/shared/log/production.log
2010/12/21 08:29:14 [4537] .d..t...... iddd/web/website/production/shared/sessions/
2010/12/21 08:29:14 [4537] >f+++++++++ iddd/web/website/production/shared/sessions/ruby_sess.017a771cc19b18cd
2010/12/21 08:29:14 [4537] >f+++++++++ iddd/web/website/production/shared/sessions/ruby_sess.01eade9d317ca79a

Let's take a look at how rsync works and better understand the cryptic result lines:

1 - A huge advantage of rsync is that after an interruption the next time it continues smoothly.

The next rsync invocation will not transfer the files again, that it had already transferred, if they were not changed in the meantime. But it will start checking all the files again from the beginning to find out, as it is not aware that it had been interrupted.

2 - Each character is a code that can be translated if you read the section for -i, --itemize-changes in man rsync

Decoding your example log file from the question:

>f.st......

> - the item is received
f - it is a regular file
s - the file size is different
t - the time stamp is different

.d..t......

. - the item is not being updated (though it might have attributes 
    that are being modified)
d - it is a directory
t - the time stamp is different

>f+++++++++

> - the item is received
f - a regular file
+++++++++ - this is a newly created item

---

The relevant part of the rsync man page:

-i, --itemize-changes

Requests a simple itemized list of the changes that are being made to each file, including attribute changes. This is exactly the same as specifying --out-format='%i %n%L'. If you repeat the option, unchanged files will also be output, but only if the receiving rsync is at least version 2.6.7 (you can use -vv with older versions of rsync, but that also turns on the output of other verbose mes- sages).

The "%i" escape has a cryptic output that is 11 letters long. The general format is like the string YXcstpoguax, where Y is replaced by the type of update being done, X is replaced by the file-type, and the other letters represent attributes that may be output if they are being modified.

The update types that replace the Y are as follows:

• A < means that a file is being transferred to the remote host (sent).
• A > means that a file is being transferred to the local host (received).
• A c means that a local change/creation is occurring for the item (such as the creation of a directory or the changing of a symlink, etc.).
• A h means that the item is a hard link to another item (requires --hard-links).
• A . means that the item is not being updated (though it might have attributes that are being modified).
• A * means that the rest of the itemized-output area contains a message (e.g. "deleting").

The file-types that replace the X are: f for a file, a d for a directory, an L for a symlink, a D for a device, and a S for a special file (e.g. named sockets and fifos).

The other letters in the string above are the actual letters that will be output if the associated attribute for the item is being updated or a "." for no change. Three exceptions to this are: (1) a newly created item replaces each letter with a "+", (2) an identical item replaces the dots with spaces, and (3) an unknown attribute replaces each letter with a "?" (this can happen when talking to an older rsync).

The attribute that is associated with each letter is as follows:

• A c means either that a regular file has a different checksum (requires --checksum) or that a symlink, device, or special file has a changed value. Note that if you are sending files to an rsync prior to 3.0.1, this change flag will be present only for checksum-differing regular files.
• A s means the size of a regular file is different and will be updated by the file transfer.
• A t means the modification time is different and is being updated to the sender’s value (requires --times). An alternate value of T means that the modification time will be set to the transfer time, which happens when a file/symlink/device is updated without --times and when a symlink is changed and the receiver can’t set its time. (Note: when using an rsync 3.0.0 client, you might see the s flag combined with t instead of the proper T flag for this time-setting failure.)
• A p means the permissions are different and are being updated to the sender’s value (requires --perms).
• An o means the owner is different and is being updated to the sender’s value (requires --owner and super-user privileges).
• A g means the group is different and is being updated to the sender’s value (requires --group and the authority to set the group).
• The u slot is reserved for future use.
• The a means that the ACL information changed.
• The x means that the extended attribute information changed.

One other output is possible: when deleting files, the "%i" will output the string "*deleting" for each item that is being removed (assuming that you are talking to a recent enough rsync that it logs deletions instead of outputting them as a verbose message).

Some time back, I needed to understand the rsync output for a script that I was writing. During the process of writing that script I googled around and came to what @mit had written above. I used that information, as well as documentation from other sources, to create my own primer on the bit flags and how to get rsync to output bit flags for all actions (it does not do this by default).

I am posting that information here in hopes that it helps others who (like me) stumble up on this page via search and need a better explanation of rsync.

With the combination of the --itemize-changes flag and the -vvv flag, rsync gives us detailed output of all file system changes that were identified in the source directory when compared to the target directory. The bit flags produced by rsync can then be decoded to determine what changed. To decode each bit's meaning, use the following table.

Explanation of each bit position and value in rsync's output:

YXcstpoguax  path/to/file
|||||||||||
||||||||||╰- x: The extended attribute information changed
|||||||||╰-- a: The ACL information changed
||||||||╰--- u: The u slot is reserved for future use
|||||||╰---- g: Group is different
||||||╰----- o: Owner is different
|||||╰------ p: Permission are different
||||╰------- t: Modification time is different
|||╰-------- s: Size is different
||╰--------- c: Different checksum (for regular files), or
||              changed value (for symlinks, devices, and special files)
|╰---------- the file type:
|            f: for a file,
|            d: for a directory,
|            L: for a symlink,
|            D: for a device,
|            S: for a special file (e.g. named sockets and fifos)
╰----------- the type of update being done::
             <: file is being transferred to the remote host (sent)
             >: file is being transferred to the local host (received)
             c: local change/creation for the item, such as:
                - the creation of a directory
                - the changing of a symlink,
                - etc.
             h: the item is a hard link to another item (requires 
                --hard-links).
             .: the item is not being updated (though it might have
                attributes that are being modified)
             *: means that the rest of the itemized-output area contains
                a message (e.g. "deleting")

Some example output from rsync for various scenarios:

>f+++++++++ some/dir/new-file.txt
.f....og..x some/dir/existing-file-with-changed-owner-and-group.txt
.f........x some/dir/existing-file-with-changed-unnamed-attribute.txt
>f...p....x some/dir/existing-file-with-changed-permissions.txt
>f..t..g..x some/dir/existing-file-with-changed-time-and-group.txt
>f.s......x some/dir/existing-file-with-changed-size.txt
>f.st.....x some/dir/existing-file-with-changed-size-and-time-stamp.txt 
cd+++++++++ some/dir/new-directory/
.d....og... some/dir/existing-directory-with-changed-owner-and-group/
.d..t...... some/dir/existing-directory-with-different-time-stamp/

Capturing rsync's output (focused on the bit flags):

In my experimentation, both the --itemize-changes flag and the -vvv flag are needed to get rsync to output an entry for all file system changes. Without the triple verbose (-vvv) flag, I was not seeing directory, link and device changes listed. It is worth experimenting with your version of rsync to make sure that it is observing and noting all that you expected.

One handy use of this technique is to add the --dry-run flag to the command and collect the change list, as determined by rsync, into a variable (without making any changes) so you can do some processing on the list yourself. Something like the following would capture the output in a variable:

file_system_changes=$(rsync --archive --acls --xattrs \
	--checksum --dry-run \
	--itemize-changes -vvv \
	"/some/source-path/" \
	"/some/destination-path/" \
| grep -E '^(\.|>|<|c|h|\*).......... .')

In the example above, the (stdout) output from rsync is redirected to grep (via stdin) so we can isolate only the lines that contain bit flags.

Processing the captured output:

The contents of the variable can then be logged for later use or immediately iterated over for items of interest. I use this exact tactic in the script I wrote during researching more about rsync. You can look at the script (https://github.com/jmmitchell/movestough) for examples of post-processing the captured output to isolate new files, duplicate files (same name, same contents), file collisions (same name, different contents), as well as the changes in subdirectory structures.

1.) It will "restart the sync", but it will not transfer files that are the same size and timestamp etc. It first builds up a list of files to transfer and during this stage it will see that it has already transferred some files and will skip them. You should tell rsync to preserve the timestamps etc. (e.g. using rsync -a ...)

While rsync is transferring a file, it will call it something like .filename.XYZABC instead of filename. Then when it has finished transferring that file it will rename it. So, if you kill rsync while it is transferring a large file, you will have to use the --partial option to continue the transfer instead of starting from scratch.

2.) I don't know what that is. Can you paste some examples?

EDIT: As per http://ubuntuforums.org/showthread.php?t=1342171 those codes are defined in the rsync man page in section for the the -i, --itemize-changes option.

Fixed part if my answer based on Joao's