If you are getting below error message while running dd command.
dd: `/dev/sda1′: cannot skip: Invalid argument
[root@nglinux ~]# dd if=/dev/sda1 of=/tmp/file4 bs=4096 count=1 skip=29661151 dd: `/dev/sda1': cannot skip: Invalid argument 0+0 records in 0+0 records out 0 bytes (0 B) copied, 0.000782975 s, 0.0 kB/s [root@nglinux ~]#
It means you are accessing wrong block “29661151”, you need to check & correct block information.
Sometimes we get the data from hdparam or fdisk, or any such disk program and copy the 512 byte block count which is wrong.
We should always get 4K block information from either filefrag command or from debugfs.
Hence you need to re-check and correct the skip block count number to resolve the issue.
The command is perfectly fine and there is no issue with that.