How to change owner of the folder on Ubuntu

Question

I have two partitions and one of them had been formated under NTFS. Ubuntu sees it like /media/DOCS. I have a web site in /media/DOCS/Dropbox/AuthoringTool_Working.
I have configured Apache and created a virtual host. When I tr to open this site it says Permission denied. I tried to change owner into www-data but have not success. I used sudo chgrp -R www-data /media/DOCS/Dropbox.
What am I doing wrong?

EDIT
It is mounted like this /dev/sda5 /media/DOCS fuseblk rw,nosuid,nodev,allow_other,blksize=4096,default_permissions 0 0

Answer 1

The NTFS filesystem does not support POSIX-style file ownership or permissions.

Some recent ntfs-3g versions have support for NTFS Owner and ACL features. I'm not sure if they are already included in Ubuntu (which usually prefers rock-solid software to new features), but from the default_permissions option in your example it does seem that your system has this support.

To change a file's owner, there must be a mapping of NTFS (Windows) SIDs to your machine's user IDs. An easy way to create such a mapping is to use usermap.

However, if a user (www-data) only exists on the Linux side, you will need to manually add it to the mapping file. (This also means that the owner will display as "unknown" when using that disk on Windows.)

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And as tamtakos already answered, to change the owner you use chown, not chgrp.

Answer 2

chgrp, as the name suggests changes the group. To change the owner of a file/directory you have to use the chown command. Of course, you can change both at the same time by doing chown root:root file Which will make 'file' belong to the root user, as well as the root group. More details on users and groups can be found here for example : http://www.yolinux.com/TUTORIALS/LinuxTutorialManagingGroups.html