Sharing & Permissions

[DanL]

I've always been a little confused about Sharing & Permissions. For most of my disks, including my startup disk, I am not listed in the Privileges pane (except as "everyone", which is listed as "Read only"), and it is listed above that "You can only read" on this disk. Duh? On all of these disks I can read and write freely in my home directory. Can someone explain to me what Sharing & Permissions is all about, and why it is telling me I can't do what I can very clearly do? Now, it is true that I can't write *anywhere* on these disks, but just in my home directory.

I have to assume what this really means is that "You can only read ANYWHERE" on this disk.

 

[maw_walker]

What this means is at the top level (/), you cannot write because that is at the root of the disk, but you can read most things on the entire disk. Permissions change depending on the directory you are in.

You also cannot write to the top level directory where your user data is stored (/Users) but you can under /Users/<your name here>. So your user can't write to /Users/<some other user>, if that makes sense.

 

[DanL]

Yes, that make sense, but the "You can only read" message isn't very accurate and somewhat confusing. Sharing & Permissions applies to everywhere but your own directory. Of course, if you chose to "Ignore ownership on this volume", you can do pretty much anything you want anywhere.

 

[maw_walker]

Well, the message is referring to "/", which is at the top level of the disk. I can see how it could be confusing though. This is how Unix permissions work though: all users have read and write to their own user directory but no where else, unless you mount an external disk and change ownership to your user. You can also read portions of the entire disk but some files you cannot, well, at least on Unix and Linux. I am not a Mac disk structure guru, despite its "Unix" status.