## Keep Cygwin Applications from setting NTFS security descriptors

If you run cygwin applications such as [the rsync-backup script](/2014/01/31/incremental-backups-with-rsync-in-windows/), you will sometimes run into trouble with odd NTFS permissions being set by the cygwin application. My tip is to avoid this by making cygwin not set *any* permissions at all. If a cygwin application then creates a file, for instance, this file will only inherit its security settings from the folder it is contained in. This way, you can set access control on the root directory and all the files created by rsync inside that folder will inherit these permissions. How to do it? Open your cygwin shell and edit /etc/fstab which should contain only one non-comment line:
none /cygdrive cygdrive binary,posix=0,user 0 0

Now insert the noacl attribute, see [the cygwin manual](http://www.cygwin.com/cygwin-ug-net/using.html#mount-table):
none /cygdrive cygdrive binary,noacl,posix=0,user 0 0

And the next time you run rsync-backup, it will *not* set all kinds of awkward permissions on your files which make them unreadable on a freshly installed computer. Just saying.

## Incremental Backups with RSYNC in Windows

I was pointed to the cool rsync-backup script which uses cygwin's rsync and hardlinks in NTFS to provide a method for incremental backups which is probably the best I have seen so far. Basically, the effect is as follows: Whenever you backup your data to the backup location (which is somewhere on an NTFS drive), the only actual data that will be copied is for the files that have changed since the last backup. Nevertheless, there will be a new folder in your backup location which contains all files and folders you just backed up. Just: Those that did not change have not been copied, they have just been hardlinked to the old files instead. Now here comes the best part: The actual contents of a file with more than one hardlink to it are deleted only after the last link to it has been removed. Thus, you can delete old backups and the only data that will actually be deleted is the old data, the data that changed in later backups. Now, I modified the script slightly to better suit my needs. First of all, I only back up a single folder. If you want to backup multiple folders to a single location, move along. This is not for you. Use the original rsync-backup if you wish. Mine is different. Do you want to know more?