I want to find those files which I cannot copy to another location such that I could do Rsync. I have an external HDD and my systems HDD. The external HDD has files which my system is missing. I am thinking how to do this. I can find those files/directories with permission denied -messages by find / ! -perm /u+rwhere some permissions are drwx------ 1  501 root       6 Oct 22  2014 PortableCV_WebCruiter_20141022The following command may work from commandlinefu.com, since remote data can be considered here as external HDDrsync --rsync-path 'sudo rsync' username@source:/folder/ /local/which Rsync remote data as root using sudo If your user has sudo on the  remote box, you can rsync data as root without needing to login as  root. This is very helpful if the remote box does not allow root to  login over SSH (which is a common security restriction).How can you rsync files with permission denied problems between external HDD and system HDD? 
To Rsync files where permission denied
permissions;find;rsync
If you want to skip the unreadable files:find /external/hd/folder ! -readable -print >unreadable_filesrsync -a --exclude-from=unreadable_files /external/hd/folder/ /local/folderThis assumes that you're using GNU find, and that your filenames don't have embedded newlines.If you want to copy all files, regardless of whether they are readable or not on the external disk:sudo rsync -a /external/hd/folder/ /local/foldersudo chown -R masi:masi /local/folderThis assumes you have enough privileges to run sudo rsync and sudo chown.