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Old 4th December 2016
alex_b83 alex_b83 is offline
Port Guard
Join Date: Oct 2015
Posts: 11

Originally Posted by bashrules View Post
This problem is then solved by setting in dd bs to a high value. Then dd and partcp should perform equally. What do you think?
As you know, this command will work slowly because of low ibs value:
dd ibs=1 if=source_file of=destination_file skip=slice_offset count=slice_length
I don't understand how to correctly replace the following command
partcp source_file slice_offset slice_length destination_file
with dd, considering that bs>1:
dd bs=high_value if=source_file of=destination_file skip=? count=?
According to dd manual page, skip and count parameters are multiples of (i)bs.
So we can't simply set them to slice_offset and slice_length, because in such case actual values will be:
skip = slice_offset * high_value and count = slice_length * high_value, which is wrong.

How do I correctly apply slice_offset and slice_length values here?

Originally Posted by Carpetsmoker View Post
This is indeed exactly the same as dd bs=4M ...
Originally Posted by alex_b83 View Post
Show me please full command line with given source_file, slice_offset, slice_length, destination_file as input values.
My question is still open.

Can you show me full command line for "dd bs=4M ..." to exactly replace the following command?
partcp source_file slice_offset slice_length destination_file
What should be written instead of ellipsis you wrote?
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