This seems to work for me: LANG=C grep –only-matching –byte-offset –binary –text –perl-regexp “<\x-hex pattern>” <file> short form: LANG=C grep -obUaP “<\x-hex pattern>” <file> Example: LANG=C grep -obUaP “\x01\x02” /bin/grep Output (cygwin binary): 153: <\x01\x02> 33210: <\x01\x02> 53453: <\x01\x02> So you can grep this again to extract offsets. But don’t forget to use binary mode … Read more
Pretty good and simple way to deal with this is simply pipe it via gzip, something like this: # dd if=/dev/sdb | gzip > backup.img.gz This way your image will be compressed and most likely unused space will be squeezed to almost nothing. You would use this to restore such image back: # cat backup.img.gz … Read more
TL;DR version: notrunc is only important to prevent truncation when writing into a file. This has no effect on a block device such as sda or sdb. Educational version I looked into the coreutils source code which contains dd.c to see how notrunc is processed. Here’s the segment of code that I’m looking at: int … Read more
The optimal block size depends on various factors, including the operating system (and its version), and the various hardware buses and disks involved. Several Unix-like systems (including Linux and at least some flavors of BSD) define the st_blksize member in the struct stat that gives what the kernel thinks is the optimal block size: #include … Read more