[ILUG] dd weirdness

[Padraig Brady]

Paul Jakma wrote:

>why does:
>
>	dd bs=1024k count=150 seek=150 if=/dev/zero of=var_fs
>
>give me:
>
>	[paulj at doohan host1]$ ls -lh
>	total 176M
>	-rw-rw-r--    1 paulj    paulj         50M Oct 12 17:10 swap
>	-rw-rw-r--    1 paulj    paulj        300M Oct 12 17:13 var_fs
>
>(the swap file was also dd'd - i wanted 25M). It also happens with 
>bs=1M.
>
>weird...
>
>--paulj
>
>
seek skips bytes on OUTPUT so you will get a 150MB hole @ the
start of the file and then the 150MB of read zeros will be written.
Why are you seeking, are you sure you don't want to skip?

Padraig.