Hi, Eduard Bloch wrote: > But for regular "push data around from FD to FD" job the only crucial > difference I remember is the nasty behavior of dd when a short read > occurres - aborting instead of retrying as cp does.
I saw it padding up short blocks and going on when i was still on SuSE 10. This happened when reading from pipes with slowly trickling data output. Jessie's dd seems to be quite ok, though $ for i in 0 1 2 3 4 ; do echo bla ; sleep 1 ; done >fifo and $ dd if=fifo bs=1024 >/tmp/dd_output 0+5 records in 0+5 records out 20 bytes (20 B) copied, 5.00444 s, 0.0 kB/s yields exactly 20 bytes in /tmp/dd_output. Not 5 KiB or 4 bytes. (It seems not to block but rather read on after each of the 4-byte lines arrived. 5 reads. 20 bytes.) The power of dd shows with commands like dd if=/dev/zero conv=notrunc bs=1 seek=446 count=1 \ of=debian-8.2.0-amd64-BD-1.iso which zeros the "bootable/active" flag of MBR partition 1. Have a nice day :) Thomas