Useful Commands
From Wikifications
Have a dying disk? Better get the data off before it's too late! disk1 is the culprit in this example.
dd conv=noerror,sync if=/dev/disk1 of=/Volumes/whatever/backup.dmg
Create an encrypted disk image that grows as needed, up to a specified maximum:
hdiutil create dmg_name -size 1g -encryption -type SPARSE -fs HFS+ -volname Vault
