My friend sent me an HFS format CD-ROM of files to look at, and it has some unhelpfully restrictive permissions. For example, here is the ls -l output for one of the directories:

d---------   4 chris  staff  136 Oct  6  2006 dir1

That is, no one has access to see the contents of the directory.

Is there any way I can get OS X to ignore the permissions on the CD and give me read access to everything on it? (Perhaps by mounting the CD myself with some funny options?) If not, is there any other way for me to read the data off the CD?

If it matters, the OS X automount facility has mounted the disk with options "hfs, local, nodev, nosuid, read-only, noowners". Is there any way I can instruct it to mount the CD

  • nosuid indicates that permissions are already turned off. That's pretty screwy. Commented Sep 17, 2010 at 7:26
  • Potatoswatter: nosuid means that set uid bit will be stripped from the permissions, not that all permissions will be turned off. This is a reasonable security setting for a disk someone has sent to you. You wouldn't want some executable you know nothing about to be running as root on your machine.
    – KeithB
    Commented Sep 17, 2010 at 13:42

2 Answers 2


I'm not sure this is the slickest way, but I seem to have a solution that involves copying the contents of the CD to the hard drive, and then correcting the permissions there.

First, copy the data to the hard drive:

  1. In the Finder, open up the CD-ROM, and select all the files/directories on the CD
  2. File...Copy
  3. Create a new folder ("cdstuff") on the hard drive somewhere
  4. Open "cdstuff" in the Finder
  5. File...Paste
  6. Finder says it needs admin access to copy the files, so enter your password when prompted.

Second, give yourself read/write permissions to the files using Terminal.app:

  1. cd cdstuff
  2. sudo chmod -R u+rwx *

Alternatively, give yourself read/write permissions using the Finder:

  1. Right-click the "cdstuff" folder, and "Get Info".
  2. Under "Sharing & Permissions", click the lock icon to enable edits.
  3. Now give "Read & Write" access to everyone.
  4. Click on the little tool/widget icon, and select "Apply to enclosed items."

If you just want to look at the disk, and perhaps copy selected files you can do that with sudo

sudo ls dir1

You can also make a copy of completely from the terminal (similar to Chris's answer)

sudo cp -R /Volumes/problemdisk /destination
sudo chmod -R 755 /destination
  • Oh, good call with "sudo ls". (And with the implied ability to copy particular files, e.g. copy dir1/file1.txt to home directory with "sudo cp dir1/file1.txt ~/".) I think I was implicitly assuming that root couldn't access files to which no one had been granted read permission; but apparently root can access any file, period.
    – Chris
    Commented Sep 17, 2010 at 16:33

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