Can't figure out what is taking up so much space When I cd /; du sudo du -h -d1 I get a total of about 160 GB (this is on a 256 GB drive). However, when I look at Disk Utility or About this Mac -> More Info -> Storage it looks like I'm using a solid 230 GB.  This is on a late 2013 Macbook Pro Retina, OS X 10.9.2.  I suspect the problem may be with mobile backups (I'm not hooked up to an external hard disk for backups).  I've tried, several times, running sudo tmutil disablelocal but that doesn't appear to fix the problem.

Here is the output of df -h after disabling local backups

/dev/disk1      233G  212G   21G  92% /

After re-enabling:

/dev/disk1                         233G  212G   21G  92% /
localhost:/ebh4eOBPvo122KL1TUyqlO  233G  233G     0 100% /Volumes/MobileBackups

Output of ls -l /Volumes/MobileBackups/Backups.backupdb/MyComputerName

total 1
drwxr-xr-x 3 root wheel 102 Jul 16 17:55 2014-07-16-175518
lrwxrwxrwx 0 root wheel   0 Jul 16 17:55 Latest -&gt; 2014-07-16-175518

Output of sudo tmutil delete 2014-07-16-175518

Deleting: /Volumes/MobileBackups/Backups.backupdb/MyComputerName/2014-07-16-175518
Error (-36) deleting: /Volumes/MobileBackups/Backups.backupdb/MyComputerName/2014-07-16-175518
Error (642) re-linking Latest for machine directory: /Volumes/MobileBackups/Backups.backupdb/MyComputerName
Total deleted: 237.4K

Any ideas?  I know very little about Macs, if that's not obvious.
To try and locate which files and directories are consuming the most disk space on your Mac, I'd recommend running OmniDiskSweeper. You can run it off of the DMG just fine. Select your hard drive and let it run and it'll list in descending order where the greatest disk usage is.

OmniDiskSweeper: https://www.omnigroup.com/download/latest/OmniDiskSweeper

From there you should hopefully be able to free up some space.

Hope this helps you!