# man dd
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seek=n Seek n blocks from the beginning of the output before copying.
On non-tape devices, an lseek(2) operation is used. Otherwise,
existing blocks are read and the data discarded. If the user
does not have read permission for the tape, it is positioned
using the tape ioctl(2) function calls. If the seek operation
is past the end of file, space from the current end of file to
the specified offset is filled with blocks of NUL bytes.
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