Update shell-and-data-access.md

docs.it4i/general/shell-and-data-access.md

@@ -179,7 +179,8 @@ local $ cd my-local-dir
 local $ ls | xargs -n 2 -P 4 /bin/bash -c 'rsync "$@" username@cluster-name.it4i.cz:mydir' sh
 ```
 
-The **-n** argument detemines the number of files to transfer in one rsync call. Set according to file size and count. The **-P** argument determines number of parallel rsync processes. Set to number of cores on your local machine.
+The **-n** argument detemines the number of files to transfer in one rsync call. Set according to file size and count (large for many small files).  
+The **-P** argument determines number of parallel rsync processes. Set to number of cores on your local machine.
 
 On Windows, use the [WinSCP client][c] to transfer data. The [win-sshfs client][d] provides a way to mount the cluster filesystems directly as an external disc.