65

I print MBR with hexdump and I get the following output:

000001a0  67 60 6f 70 65 72 61 74  69 6e 67 60 73 79 73 74  |g`operating`syst|
000001b0  65 6d 00 40 00 63 7b da  c5 f5 61 68 00 40 00 40  |em.@.c{...ah.@.@|
000001c0  00 40 00 40 00 40 00 40  00 40 00 40 00 40 00 40  |.@.@.@.@.@.@.@.@|
*
000001f0  00 40 00 40 00 40 00 40  00 40 00 40 00 40 55 ea  |.@.@.@.@.@.@.@U.|
00000200

What does the astersik * mean in the output?

3
  • It's dump and it means same as above.
    – ott--
    Oct 27, 2012 at 21:45
  • OK, wonderfull, I was guessing it, but just wanted be sure :) Can you put it as answer?
    – Rodnower
    Oct 27, 2012 at 21:55
  • * can mean more than one line be careful.
    – Smeterlink
    Apr 6, 2020 at 13:04

2 Answers 2

82

A line in the hexdump output consisting just a * means same as the line above. This is mentioned in the hexdump's manpage at the -v option (easy to be overlooked).

4
  • 1
    Thanks! That was super important for my parser to take into account!
    – BuvinJ
    Jul 21, 2016 at 21:03
  • 10
    @BuvinJ (or rather anyone else): You can just pass -v to avoid this, so that your parser doesn't need to take it into account. Mar 25, 2017 at 3:05
  • * can mean one line of more, as many as there are until the proper offset.
    – Smeterlink
    Apr 6, 2020 at 13:05
  • This is super confusing when it's actually the first and only thing that hexdump shows, but what it really means is you've got a file with nothing but zeros in it.
    – detly
    Jul 27, 2021 at 1:12
1

As mentioned in the comments, without to verbose option to hexdump, -v, the asterisk indicates "same as above". Most likely seen on empty files or parts thereof:

> hexdump -C -s 12 -n 32 test-data/blk00000.dat
0000000c  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
*
0000002c

Adding the option -v to hexdump gives the full result, which is especially useful, if the output is used as input to some other process:

> hexdump -v -C -s 12 -n 32 test-data/blk00000.dat
0000000c  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
0000001c  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
0000002c

(Answer added for completeness)

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.