UNIX for Advanced & Expert Users

I wasn't asking anything, actually, but thank you for the clarification

ACLs can be a pain, especially when used with nested folders, but when they work they are a great. I did notice that on the newest version of OS X (which I know is it's own version of Unix) has some custom default ACLs "everyone:deny" on certain folders in every user's home directory, by default.

Hi ceubank, would you please be able to explain what does this means interms of the last options colomn? Does rw means that the current user who issue this mount command has rw access to the file system(/apps/z0/log) even the files in there belong to someone else and permissions are say 700 ?

Thanks in advance.

Code:

f8fmil: /apps/z0/log/new2/Jr>mount -o acl
  node       mounted        mounted over    vfs       date        options      
-------- ---------------  ---------------  ------ ------------ --------------- 
         /dev/hd4         /                jfs2   Nov 18 15:52 rw,log=/dev/hd8 
         /dev/hd2         /usr             jfs2   Nov 18 15:52 rw,log=/dev/hd8 
        /dev/lvappz0log /apps/z0/log   jfs2   Nov 18 15:53 rw,log=/dev/lg_appvg01

No, it just means the filesystem is mounted as read-write, letting people read and write according to their normal permissions, as opposed to read-only.

Without ACL's, directory permissions are the only thing describing who can and can't delete files. File permissions and ownership are irrelevant. Observe:

Code:

$ mkdir tmp
$ touch tmp/notouch
$ chmod 000 tmp/notouch
$ sudo chown root:root tmp/notouch
# You can delete a root-owned file with 000 permissions, if it's in your dir!
$ rm tmp/notouch

---------- Post updated at 10:07 AM ---------- Previous update was at 09:49 AM ----------

I had to do some testing to figure it out, but the sticky bit could help do what you want. It's also known as the restricted-deletion bit. On supported systems&filesystems, inside a directory with it set(with chmod +t), users cannot rename or remove files that don't belong to them. It's often used for /tmp.

(Note that this protection is short-circuited if the user in question actually owns the directory. Have it owned by root or something.)

Using ACLs, you chould just do:

Code:

chmod +a "others allow delete" filename

to allow others to delete a file using ACLs , you can view these permissions with ls -le to see the ACL flags set.. if you have a directory and you want to allow people to delete things in it you would do others allow delete_child.

This may be a bit off topic, but you can also set flags via chflags command. You can make so files cannot be deleted or modified at all.

DragonFly On-Line Manual Pages : chflags(1)

I'm not much of an AIX person, but try the 'aclget' command.. that might help..?

The user mounting the filesystem is somewhat irrelevant..

Another possibility is the 'rm' command being aliased to something like

alias rm='sudo rm -i'

with sudoers file being set up to restrict the command.