#!/bin/bash
# just a script to help with some disk rescue that involves cd writing
#
# constants
    # edit these to suit
        # disk info in MB, where 1MB = 1024*1024 bytes = 1048576 bytes
        diskend=24380
        chunk=660
        # which disk
        disk=/dev/hdd
        # get a name for dd's output, tail of $disk above,
        # to be combined with the count later
        fname=/dev/hdb5
    # blocksize, in bytes, used in dd
    # 1MB (1024 * 1024) is chosen here
    block=1048576
    # bytes in a sector
    sector=512
    # sectors per block
    secb=$((${block} / ${sector}))
    numchunks=$(($(echo "${diskend} / ${chunk}" | bc ) + 1))
# counters
skip=0
cnt=0
while [ ${cnt} -lt ${numchunks} ]
do
    start=$((${cnt} * ${chunk}))
    end=$((${start} + ${chunk}))
    if [ ${end} -gt ${diskend} ]
        then
            chunk=$((chunk - (${end} - ${diskend})))
            end=$((${diskend}))
    fi
    fpre=$((${cnt}+1))
    if [ ${fpre} -lt 100 ]
        then
            fpre=0${fpre}
    fi
    if [ ${fpre} -lt 10 ]
        then
            fpre=0${fpre}
    fi
    secst=$((${start} * ${secb}))
    secen=$((${end} * ${secb}))
    echo "${fpre}  dd if=${disk} of=${fname} bs=${block} skip=0 seek=${skip} count=${chunk}"
    echo "		(start=${start}MB, ${secst}s,  end=${end}MB, ${secen}s)"
    skip=$((${skip} + ${chunk}))
    cnt=$((${cnt} + 1))
done
echo "chunks=${numchunks}"