Commands using shred (11)

  • securely erase unused blocks in a partition

    This command securely erases all the unused blocks on a partition. The unused blocks are the "free space" on the partition. Some of these blocks will contain data from previously deleted files. You might want to use this if you are given access to an old computer and you do not know its provenance. The command could be used while booted from a LiveCD to clear freespace space on old HD. On modern Linux LiveCDs, the "ntfs-3g" system provides ReadWrite access to NTFS partitions thus enabling this method to also be used on Wind'ohs drives. NB depending on the size of the partition, this command could take a while to complete. Show Sample Output


    8
    # cd $partition; dd if=/dev/zero of=ShredUnusedBlocks bs=512M; shred -vzu ShredUnusedBlocks
    mpb · 2009-06-21 14:17:22 13
  • How to secure delete a file

    Instead, install apt-get install secure-delete and you can use: -- srm to delete file and directory on hard disk -- smem to delete file in RAM -- sfill to delete "free space" on hard disk -- sswap to delete all data from swap


    6
    shred -u -z -n 17 rubricasegreta.txt
    0disse0 · 2010-01-31 15:24:54 8
  • Erase to factory a pendrive, disk or memory card, and watch the progress


    6
    sudo shred -vz -n 0 /dev/sdb
    bugmenot · 2012-08-06 22:37:44 7
  • Securely destroy data (including whole hard disks)

    GNU shred is provided by the coreutils package on most Linux distribution (meaning, you probably have it installed already), and is capable of wiping a device to DoD standards. You can give shred any file to destroy, be it your shell history or a block device file (/dev/hdX, for IDE hard drive X, for example). Shred will overwrite the target 25 times by default, but 3 is enough to prevent most recovery, and 7 passes is enough for the US Department of Defense. Use the -n flag to specify the number of passes, and man shred for even more secure erasing fun. Note that shredding your shell history may not be terribly effective on devices with journaling filesystems, RAID copies or snapshot copies, but if you're wiping a single disk, none of that is a concern. Also, it takes quite a while :)


    5
    shred targetfile
    sud0er · 2009-04-28 19:57:43 11
  • Safe Delete

    remove file that has sensitive info safely. Overwrites it 33 times with zeros


    2
    shred -n33 -zx file; rm file
    copremesis · 2009-05-08 19:15:41 48
  • Realy remove file from your drive

    This command remove a file from your filesystem like the normal rm command but instead of deleting only the inode information this also delete the data that was stored on blocks /!\ warning this may be long for large files Show Sample Output


    1
    function rrm(){ for i in $*; do; if [ -f $i ]; then; echo "rrm - Processing $i"; shred --force --remove --zero --verbose $i; else; echo "Can't process $i"; type=$(stat "$1" -c %F); echo "File $i is $type"; fi; done;}
    thelan · 2010-06-10 22:40:27 8
  • securely overwrite a file with random junk, rename it to clear the directory entry and finally delete it

    Show Sample Output


    0
    shred -vzu /tmp/junk-file-to-be-shredded
    mpb · 2009-06-18 12:00:19 12
  • Destroy file contents after encryption

    Make sure the file contents can't be retrieved if anyone gets ahold of your physical hard drive. With hard drive partition: gpg --default-recipient-self -o /path/to/encrypted_backup.gpg -e /dev/sdb1 && shred -z /dev/sdb1 WARNING/disclaimer: Be sure you... F&%k it--just don't try this.


    0
    gpg -e --default-recipient-self <SENSITIVE_FILE> && shred -zu "$_"
    h3xx · 2011-07-24 05:51:47 4
  • Completly blank a disk

    Instead of zeroing the filesystem, this command overwrites N times (default is 3) the disk content, making data recovery much harder. The command accepts many more options


    0
    shred --iterations=N /dev/sdaX
    bibe · 2012-01-23 20:40:36 9
  • Shred an complete disk, by overwritting its content 10 times

    Shred can be used to shred a given partition or an complete disk. This should insure that not data is left on your disk


    -2
    sudo shred -zn10 /dev/sda
    dcabanis · 2009-04-30 13:02:43 9
  • Delete a file securely by overwriting its contents


    -5
    shred -v filename
    techie · 2013-05-07 14:58:17 7

What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Share Your Commands

Check These Out

List files older than one year, exluding those in the .snapshot directory
Useful when you want to cron a daily deletion task in order to keep files not older than one year. The command excludes .snapshot directory to prevent backup deletion. One can append -delete to this command to delete the files : $ find /path/to/directory -not \( -name .snapshot -prune \) -type f -mtime +365 -delete

List the size (in human readable form) of all sub folders from the current location
Sorted in human readable format.

For finding out if something is listening on a port and if so what the daemon is.
See what's listening on your IPv4 ports on FreeBSD.

SVN Status log to CSV
Note you have also the --xml option ;)

Clear all Windows Event Log entries (cygwin)
Efficiently clear all Windows Event log entries from within a Cygwin terminal. Uses "cygstart" to launch a hidden "PowerShell" session passing a Powershell command to loop through and clear all Windows Event Log entries. Very useful for troubleshooting and debugging. The command should in theory elevate you session if needed. One liner is based on the PowerShell command: $ wevtutil el | foreach { wevtutil cl $_ }

Mortality Countdown
watch the seconds of your life tick away - replace YYYY-mm-dd HH:MM:ss w/ your birthtime.

Copy uncommitted changes from remote git repository
Copy changed files from remote git repository, _including binary ones_, staged and unstaged alike. Note that this command doesn't handle deleted files properly.

cd into another dir to run a one-liner, but implicitly drop back to your $OLD_PWD after
Obviously the example given is necessarily simple, but this command not only saves time on the command line (saves you using "cd -" or, worse, having to type a fully qualified path if your command cd's more than once), but is vital in scripts, where I've found the behaviour of "cd -" to be a little broken at times.

the executable that started the currently running oracle databases and the ORACLE_HOME relative to each
get a list of currently running oracle dbs (identified by the pmon process) show the executable that spawned the process and show the ORACLE_HOME relative to the environment within which the process is running tailored to AIX (sed on linux behaves...differently) suggestions for a better way...please.

Find all dot files and directories

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for: