0      Success

1      Syntax or usage error

2      Protocol incompatibility

3      Errors selecting input/output files, dirs

4      Requested action not supported: an attempt was made to manipulate 64-bit files on a platform that cannot support them; or an option was specified that is supported by the client and not by the server.

5      Error starting client-server protocol

6      Daemon unable to append to log-file

10     Error in socket I/O

11     Error in file I/O

12     Error in rsync protocol data stream

13     Errors with program diagnostics

14     Error in IPC code

20     Received SIGUSR1 or SIGINT

21     Some error returned by waitpid()

22     Error allocating core memory buffers

23     Partial transfer due to error

24     Partial transfer due to vanished source files

25     The --max-delete limit stopped deletions

30     Timeout in data send/receive

记录一个rsync返回12的错误

ERROR: cannot overwrite non-directory with a directory
rsync error: errors selecting input/output files, dirs (code 3) at main.c(488) [receiver=2.6.8]
rsync: connection unexpectedly closed (4 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(600) [sender=3.0.6]

这个是因为把一个文件作为目录来rsync了