Linux File System ACLs permission Control (1)

The Linux File System grants the owner (owner), owning group (owning group), and other) the rwx permissions defined for each type of users are independent of each other. Although Linux supports special file permissions in Linux, it is necessary to control permissions in Windows to be precise to users and groups. For example, to allow a file to be modified by a special user, allows a group of users to view and so on) as flexible, these are obviously not enough. Fortunately, Linux also supports ACLs permission control. In Linux, ACLs is supported in file systems such as ReiserFS, Ext2, Ext3, JFS, and XFS.

Modify the file ACL: setfacl-m u: tux: rw file allows tux to Read and Write file files.

View file ACL: getfacl file

When you use the ls-l command to view the ACL file, there will be a "+" next to it, and the group permission will change with the ACL mask permission ).

After an ACL is used for a file, the permission role has the following types:

Minimize ACL:

Owning user

Owning group

Other

Extended ACL:

Can contain several objects: named user sets the access permissions of individual users), named group sets the access permissions of individual groups)

Contains a mask that limits the permissions of named users and named groups)

Example:

Owner user: rwx

Named user: name: rwx

Owning group: rwx

Named group: nam e: rwx

Mask: rwx

Other: rwx

Permissions defined in owner and other are always valid. other permissions may be valid or hidden.

Whether the value of the named user and named group takes effect depends on the value and the value of the mask. That is, the value must have this permission to take effect.

The value of the mask is generally the same as that of the owning group. You can modify the value of the owning group to modify the mask.