## Only New Files
(From [here](https://unix.stackexchange.com/questions/67539/how-to-rsync-only-new-files))

The issue might be caused by different user/group IDs on source and target servers. My case was similar, having all files transferred instead of only the modified/new ones. The solution was to use parameters `-t` (instead of `-a`), and `-P` (equivalent to `--partial --progress`):

```
rsync -h -v -r -P -t <source> <target>
```h
or shorter (thanks @Manngo);
```
rsync -hvrPt <source> <target>
```
This transfers only new files, and files already existing but modified. Parameter -a does too much, like user and group ID sync, which in my case can not work as I have different users and groups on my source and target systems. Therefore with `-a` all my source and target files were always regarded as "different".

The parameters in detail:

```csv sep=: cols=2 vert hpad
csvhead: Switch: Description
`-h`: human readable numbers
`-v`: verbose
`-r`: recurse into directories
`-P`: `--partial` (keep partially transferred files) + `--progress` (show progress during transfer)
`-t`: preserve modification times
```

# Resources
* [stackexchange](https://unix.stackexchange.com/questions/67539/how-to-rsync-only-new-files)