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Subsections


File Security

Unlike standard NFS UNIX file permissions, AFS uses Access Control Lists, or ACLs, to control permissions on a directory and the files contained in it; ACLs allow you to specify users who have permission to use a particular directory, as well those users' specific permissions to that directory.

(Refer to the Using chmod section of this document for an explanation of further differences between the NFS and AFS file systems.)   Since ACLs are defined for directories rather than files, the permissions specified by a directory's ACL affect all the files in that directory, rather than affecting the individual files. For example, you can define an ACL that lets two users read and modify files in a directory, while a third user can only read them.   

Current Setup

When you first log on with your Rensselaer userID and use the ls command to check to see what's in your home directory, you will discover that it includes the public and private subdirectories.     The public directory gives all users lookup and read access; this means that other users can view the contents of your files in this directory, or copy files to their own directories for their own use. By contrast, other users have no access at all to the files contained within your private directory. Therefore, the easiest way for you to give others read access to your files is to copy the files into your public directory, and the easiest way to keep files hidden is to move them into your private directory.

You also have a yesterday directory within your computer account, and this contains copies of all your files as of the most recent system backup. However, since this directory does not use up any of the space in your disk quota allotment, do not try to change the permissions within this directory, or to delete files.

Please note that any new directories which you create with the mkdir command will have the same permission as their parent directories unless you change them, as outlined below.


next up previous contents
Next: Understanding File Permissions Up: Sharing Files on RCS Previous: Introduction
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