#! /bin/bash
#
# Shell skript for secure and relative fast setting to length zero.
# It overrites the file with random bytes and sets the file length to
# zero.
# For secure emptying.
#
# For using another random number device than /dev/random change 
# the if-option of dd below.
#
# First version: with dd and bs=1 (slow).
#
# TODO: Version which works with special signs like newline in the file
# name and which converts the file names with their absolute path
# because otherwise find can read them as options if they have the same name.
#
# rolf dot freitag at email.de 2000

for file in "$@"
do
  size=`find "$file" -printf "%s"` || continue
  # overrite all bytes of the file
  # dd if=/dev/urandom of="$file" bs=1 count=$size #(old version)
  ddrescue -v --max-size=$size /dev/urandom "$file"
  # set size to 0; see also "Unix Power Tools"
  > "$file"
done  

exit 0