disk-mgmt/ddwrite

   1 #!/bin/sh
   2
   3 set -u
   4
   5 usage="[DDWRITE_REWIND=<sectors>] [DDWRITE_INCREMENT=<sectors>] ddwrite <device> [<initial-seek>]"
   6 rewind_sectors=${DDWRITE_REWIND:-10}
   7 increment=${DDWRITE_INCREMENT:-10000}
   8
   9 devpath=${1?$usage}
  10 if [ ! -e "$devpath" ]
  11 then
  12         echo "$usage" >&2
  13         exit 255
  14 fi
  15 seek=${2:-0}
  16
  17 while true
  18 do
  19         echo "ddwrite: device=$devpath seek=$seek" >&2
  20         ddoutput=`LANG=C dd if=/dev/zero of="$devpath" bs=512 oflag=direct seek=$seek count=$increment 2>&1`
  21         echo "$ddoutput" >&2
  22         if expr "$ddoutput" : '.*No space left on device' >/dev/null
  23         then
  24                 break
  25         fi
  26         sectors=`echo "$ddoutput" | grep "records out" | tail -n1 | sed -e "s/[^0-9].*//"`
  27         seek=$(( seek + sectors - ( sectors < increment ? rewind_sectors : 0 ) ))
  28 done