hexdump

Show file hexadecimal format

Supplementary instructions

hexdump command is generally used to view the hexadecimal encoding of "binary" files, but in fact it can view any file, not just binary files.

grammar

hexdump [options] [file]...

Options

-n length Format only the first length bytes of the input file.
-C Output canonical hexadecimal and ASCII codes.
-b Single-byte octal display.
-c Single-byte character display.
-d Double-byte decimal display.
-o Double-byte octal display.
-x Two-byte hexadecimal display.
-s Start output at offset.
-e specifies the format string. The format string is contained in a pair of single quotes. The format string is in the form: 'a/b "format1" "format2"'.

Each format string consists of three parts, each separated by spaces. The first one is in the form a/b, where b means to apply format1 format to each b input bytes, and a means to apply format2 format to each a input bytes. , generally a>b, and b can only be 1, 2, 4. In addition, a can be omitted, if omitted, a=1. Format strings similar to printf can be used in format1 and format2, such as:

%02d: two decimal places
%03x: three digits of hexadecimal
%02o: two-digit octal
%c: single character, etc.

There are also some special uses:

%_ad: Marks the sequence number of the next output byte, expressed in decimal.
%_ax: Marks the sequence number of the next output byte, expressed in hexadecimal.
%_ao: Marks the sequence number of the next output byte, expressed in octal.
%_p: Use . to replace characters that cannot be displayed as regular characters.

If you want to display multiple format strings on the same line, you can follow multiple -e options.

Example

hexdump -e '16/1 "%02X " " | "' -e '16/1 "%_p" "\n"' test
00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F | ............
10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F | ............
20 21 22 23 24 25 26 27 28 29 2A 2B 2C 2D 2E 2F | !"#$%&'()*+,-./