Hi
we have a group in our network named 'trainings' also a directory named Docs.the members under trainings could read the files under Docs.but they should'nt copy Docs directory and it's files .how can i give the permisssion?

Anybody can help me....

Let me get this straight: so you mean that the users in group trainings must have a read access to the directory Docs/, but they should not be able to copy the contents of that directory nor the directory itself (as a whole)? If I misunderstood, please correct me

Anyway if I got that right, it might be tricky. I mean if they have read permissions, they can read (and thus copy) the files; you can prevent them from writing to that directory, or any place else on the system, but they can nevertheless copy the information and possibly paste it to some other system/place. That's what reading is you could of course write somekind of "user interface" which lets them read files from within that directory somehow that they were unable to copy them, but it might prove difficult..

What's the idea behind letting them see the files inside Docs/ but prevent them from copying what they see anyway? I mean, they could (at worst) just write down the information manually..that's copying too. I hope I misunderstood something, but correct me in that case.

If they have UNIX read access then sorry. If they can access with any viewer, then they can use cp as viewer. If you try to make an UI for them in a good LAN, you can possibly allow them chroot'ed SSH logins with X forwarding and make the following chain: daemon on the machine reads data and passes via local TCP socket to the only (statically linked) program that resides inside chroot. Then this programs renders itself an image and passes it to X server. In this case there will be only screenshots and manual writing down. If you want to forbid screenshots you have to use very restricted-access machines that have no removable media capabilities (check USB is disabled) and that cannot send anything by network. If there is any possibility to take information away, it will be used, and getting a screenshot is not difficult. If you want to prevent writing down, you'll need administrative measures like full search of everyone going away and you can drop all other measures except network isolation not to let mailing files.