Tips for using hexdump

During development, you often need to view the content of non-text files. The most common hexadecimal viewer is hexdump. Hexdump seems simple, but it still has some tips.

The text file tmpfile is used as an example:

Click (here) to fold or open

Happy New Year! Happy New Year!
Happy New Year! 1) The simplest way
Hexdump testfile



0000000 6148 7070 2079 654e 2077 6559 7261 0a21 * 0000030


This method takes two bytes as a group, and the order depends on the local byte order. For example, in the x86 architecture, it is displayed in the blittle-endian mode, and it looks very difficult.
For example, the first line is translated into an ascii code:
6148 7070 2079 2077 654e 6559 7261 0a21
AH pp y Ne w e AE! R

To avoid this situation, we need to use the following "view in byte mode"

2) view in bytes
Hexdump-C testfile-s skip-n number



00000000 48 61 70 70 79 20 4e 65 77 20 59 65 61 72 21 0a | Happy New Year !. | * 00000030


In this way, there will be no problem with the byte order, and the hexadecimal and ascii code can be displayed at the same time. However, the problem is that if the content of several rows is the same, the last few lines will be omitted, which sometimes causes trouble. How can we avoid omitting it?

3) do not omit
Hexdump-v testfile



0000000 6148 7070 2079 654e 2077 6559 7261 0a21 0000010 6148 7070 2079 654e 2077 6559 7261 0a21 0000020 6148 7070 2079 654e 2077 6559 7261 0a21 0000030


If we omit it, But it returns to the old road where two bytes are displayed, we need to combine the two methods.

4) display in byte mode and do not omit
Hexdump-Cv testfile



00000000 48 61 70 70 79 20 4e 65 77 20 59 65 61 72 21 0a | Happy New Year !. | 00000010 48 61 70 70 79 20 4e 65 77 20 59 65 61 72 21 0a | Happy New Year !. | 00000020 48 61 70 70 79 20 4e 65 77 20 59 65 61 72 21 0a | Happy New Year !. | 00000030


Now we can see more. It is displayed in a single byte format and will not be omitted. But sometimes the file is very large. We only want to check one of them. How can this problem be solved?

5) display a Section
Hexdump-Cv testfile-s skip-n number



Fireaxe $ hexdump-Cv tmp.txt-n 1 00000000 48 | H | 00000001 Fireaxe $ hexdump-Cv tmp.txt-n 2 00000000 48 61 | Ha | 00000002 Fireaxe $ hexdump-Cv tmp.txt-n 3 00000000 48 61 70 | Hap | 00000003

Fireaxe $ hexdump-Cv tmp.txt-s 1-n 1 00000001 61 | a | 00000002 Fireaxe $ hexdump-Cv tmp.txt-s 2-n 1 00000002 70 | p | 00000003 Fireaxe $ hexdump-Cv tmp.txt-s 3-n 1 00000003 70 | p | 00000004


OK. You can control the entire display process ~~