dd quickref

gistfile1.txt

https://medium.com/@pranavt84/postgresql-page-structure-a-deep-dive-e82094a613de

seek= how far you go ahead in the output file

skip= how far you go ahead in the input file

count= how many segments you copy (can be set via bs=)

say you have 2 16 byte files like so:

file1: 00 11 22 33 44 55 66 77 88 99 AA BB CC DD EE FF

file2: 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01 01

heres some commands and sample outputs:

dd if=file1 of=file2 count=12 bs=1 seek=4
file2: 01 01 01 01 [00 11 22 33 44 55 66 77 88 99 AA BB]


dd if=file1 of=file2 count=12 bs=1 skip=4
file2: [44 55 66 77 88 99 AA BB CC DD EE FF] 01 01 01 01

dd if=file1 of=file2 count=12 bs=1 skip=4 seek=4 count=8
file2: 01 01 01 01 [44 55 66 77 88 99 AA BB] 01 01 01 01