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--- docs:mac:fsck [2007/01/23 08:39] – created billh
+++ docs:mac:fsck [2008/08/03 00:25] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 ====== fsck (Mac)======
 |(hold) command-s|start up in single user mode|
+|df  |display disk free space, along with disk names (most useful when you are not in single user mode, so you can see the full drive list) |
 |/sbin/fsck -fy  |run a filesystem consistency check and interactive repair, assuming yes to all questions (the -f means check a disk even if it is clean)|
 |/sbin/fsck -fn  |run a filesystem consistency check and interactive repair, assuming no to all questions, and do not open the disk for writing|
@@ Line 6: / Line 7: @@
 |exit            |startup without rebooting|
 |diskutil verifyVolume /|Verify the disk structure of a volume.  Ownership of the affected disk is required.|
+===== BAD SUPERBLOCK / MAGIC NUMBER WRONG =====
+If you are trying to run fsck on a disk other than the main boot disk, you may see this error:
+<code>
+BAD SUPER BLOCK: MAGIC NUMBER WRONG
+</code>
+...so run this instead:
+<code>
+/sbin/fsck_hfs -fy /dev/rdisk0s3
+</code>
+Other Operating System references talk about using newfs -N /dev/diskname to get a list of super-block backups, any of which can be used with the -b flag of fsck to make things work.  This is not the case with Mac / HFS, so use fsck_hfs instead.
+===== External Links =====
+  * [[http://docs.info.apple.com/article.html?artnum=106214|Resolve startup issues and perform disk maintenance with Disk Utility and fsck]]
+  * [[http://www.osxfaq.com/Tutorials/fsck/index.ws|How To Run fsck To Examine A Non-boot Volume In Mac OS X]]