Been three years since I did it. I split an 80gb drive up between 9 .img files I vaguely remember doing it but don't remember anything more than that.
I suspect whatever command I used automatically split the files but I might have did the "skip" "seek" thing. They are compressed.
I was able to restore the image to the original 80gb drive (sda)
cat file.000 file.001 file.002 file.003 etc. | gunzip -c | dd of=/dev/sda conv=sync,noerror bs=64K
but it was not readable. So I formatted it and than tried dd to (sda1) the drive was no longer readable. No error's (both times) it finished completely.
76848496640 (77gb) copied, 1015.14 s, 75.7 mb/s
tried joining the files with cat and piping to gzip got a 33gb image file. tried ntfsclone on that unfortunately I don't remember the error I got.
what's odd is how dd managed to copy 77gb to the drive when the uncompressed version of the file was only 33gb.
cat file.000 file.001 file.002 etc. | gunzip -c | ntfsclone --restore-image --overwrite /dev/sda1 -
cat file.* | gunzip -c | ntfsclone -r -O /dev/sda1
I should have kept a pad handy to write down all the errors but didn't think of it at the time. Neither command worked.
If I search enough I might find the page I used as a template to generate the files but was hoping maybe somebody is familiar enough with ntfsclone to know what I did wrong. (assuming it's a ntfsclone file)
It could be ddrescue tried that also and it said something to the effect no input output file:
cat file.000 file.001 file.002 etc. | gunzip -c | ddrescue /dev/sda1
Used trinity rescue disk both to generate the file and in my attempt to recover it.