The wipe command can be used to securely erase files from magnetic media.
sudo apt install wipe
wipe [options] <target>
Usage: wipe [options] files...
Options:
-a Abort on error
-b <buffer-size-lg2> Set the size of the individual i/o buffers
by specifying its logarithm in base 2. Up to 30 of these
buffers might be allocated
-c Do a chmod() on write-protected files
-D Dereference symlinks (conflicts with -r)
-e Use exact file size: do not round up file size to wipe
possible junk remaining on the last block
-f Force, i.e. don't ask for confirmation
-F Do not attempt to wipe filenames
-h Display this help
-i Informative (verbose) mode
-k Keep files, i.e. do not remove() them after overwriting
-l <length> Set wipe length to <length> bytes, where <length> is
an integer followed by K (Kilo:1024), M (Mega:K^2) or G (Giga:K^3)
-M (l|r) Set PRNG algorithm for filling blocks (and ordering passes)
l Use libc's random() library call
a Use arcfour encryption algorithm
-o <offset> Set wipe offset to <offset>, where <offset> has the
same format as <length>
-P <passes> Set number of passes for filename wiping.
Default is 1.
-Q <number> set number of passes for quick wipe
-q Quick wipe, less secure, 4 random passes by default
-r Recurse into directories -- symlinks will not be followed
-R Set random device (or random seed command with -S c)
-S (r|c|p) Random seed method
r Read from random device (strong)
c Read from output of random seed command
p Use pid(), clock() etc. (weakest)
-s Silent mode -- suppresses all output
-T <tries> Set maximum number of tries for free
filename search; default is 10
-v Show version information
-Z Do not attempt to wipe file size
-X <number> Skip this number of passes (useful for continuing a wiping operation)
-x <pass1,pass2,...> Define pass order
wipe -r /media/b/1GB-USB
Okay to WIPE 1 directory ? (Yes/No) yes
Wiping 1.h2w, pass 0 (0 ) 4305 / 60718] ETA 3h08m