Selling that Computer? Wipe Out Personal Files First
This is a re-post from a year ago. diglloydTools is compatible with macOS High Sierra.
Note: the 2017 model is much improved and now my main workstation.
The iMac 5K has gone back to Apple (see comments on why it’s a fine machine but just not for me). See also the review of the iMac 5K.
Having copied over my stuff including mail and source code and various, I didn’t really like the idea of just emptying the trash, so I wanted a fast and efficient way to overwrite my files.
Enter the wipe command command in diglloydTools, which wipes files efficiently without any need to erase the drive. The command also wipes out metadata in the file system catalog as well as renaming each file to a random long gibberish name, before finally deleting it. Double confirmation is needed before any files are actually wiped.
NOTE: the wipe and wipeFree commands are available in Terminal (command line) only at present (advanced users).
- A full erase/wipe is always better if the drive is to be sold, but this is not viable or convenient when/if the drive is in active and continued use. (Very high security requirements would require physical destruction of the drive, or at the least, a complete erase and block-level wipe by booting off another drive).
- Since wiping files on an SSD doesn’t really wipe those actual blocks, I followed the wipe-files command with the dgl wipeFree command, letting it erase all free space down to the last free byte. Then I repeated; with most of the drive unused, this effectively cycles through all blocks on the SSD.
The wipe command also supports an easy to use convenience feature: appending the suffix -wipeMe to any file or folder tags it for wiping (“dgl wipe”). All local volumes are scanned for such files in highly efficient fashion, making it convenient to mark many items for wiping, then do it in one invocation.
Other users for wiping free space
As it turns out, my most frequent use of the wipeFree command is to wipe free space on Disk Utility disk images so that they compress down to the smallest possible size (e.g. when I zip compress one for downloading).
- Reader Feedback: “WORTH it. My drive (SSD) is back and so is my productivity”
- How to Safely Transfer Data or Verify Backups