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 6
  • 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 0
  • 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 0
  • 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 5
  • 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 3
  • 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 0
  • 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 2
  • 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 0
  • 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 0
  • 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 3
  • Delete a file securely by overwriting its contents


    -5
    shred -v filename
    techie · 2013-05-07 14:58:17 0

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Get AWS temporary credentials ready to export based on a MFA virtual appliance
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Convert seconds to [DD:][HH:]MM:SS
Converts any number of seconds into days, hours, minutes and seconds. sec2dhms() { declare -i SS="$1" D=$(( SS / 86400 )) H=$(( SS % 86400 / 3600 )) M=$(( SS % 3600 / 60 )) S=$(( SS % 60 )) [ "$D" -gt 0 ] && echo -n "${D}:" [ "$H" -gt 0 ] && printf "%02g:" "$H" printf "%02g:%02g\n" "$M" "$S" }

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Batch convert files to utf-8
taken from http://blog.ofirpicazo.com/linux/batch-convert-files-to-utf-8/

Remove security limitations from PDF documents using QPDF
Remove security restrictions from PDF documents using this very simple command on Linux and OSX. You need QPDF installed (http://qpdf.sourceforge.net/) for this to work.

Identify long lines in a file
This command displays a list of lines that are longer than 72 characters. I use this command to identify those lines in my scripts and cut them short the way I like it.

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