Shell command: od

od dumps the content of files. By default, in octal format, but other formats (such as hex numbers) can be chosen

od [OPTION]… [FILE]… od [-abcdfilosx]… [FILE] [[+]OFFSET[.][b]] od --traditional [OPTION]… [FILE] [[+]OFFSET[.][b] [+][LABEL][.][b]]

Instead of FILE, - can be specified, which reads stdin.

Options

Arguments to long options are connected to the option name with a = sign.

`-A`	`--address-radix=`	`RADIX`	output format for file offsets (left most column); RADIX is one of [doxn], for Decimal, Octal, Hex or None
	`--endian=`	`big` or `little`	swap input bytes according the specified order
`-j`	`--skip-bytes=`	`nofBytes`	skip `nofBytes` input bytes first
`-N`	`--read-bytes=`	`nofBytes`	limit dump to `nofBytes` input bytes
`-S`	`--strings=`	`nofBytes`	Output strings of at least `nofBytes` graphic chars; `3` is implied when optional `nofBytes` is not specified
`-t`	`--format=`	`TYPE`	select output format or formats
`-v`	`--output-duplicates`		Do not use `*` to mark line suppression
`-w`	`--width=`	`nofBytes`	put `nofBytes` per output line; `32` is implied when optional `nofBytes` is not specified
	`--traditional`		?
	`--help`
	`--verion`		Print version.

`a`	Named character, ignoring high-order bit	`-t a` can be abbreviated with `-a`
`c`	Printable character or backslash escape	`-t c` = `-c`
`d[SIZE]`	Signed decimal, SIZE bytes per integer	`-t dI` = `-i`, `-t dL` = `-l`, `-t d2` = `-s`
`f[SIZE]`	Floating point, SIZE bytes per float	`-t fF` = `-f`
`o[SIZE]`	Octal, SIZE bytes per integer	`-t o1` = `-b`, `-t o2` = `-o`
`u[SIZE]`	Unsigned decimal, SIZE bytes per integer	`-t u2` = `-d`
`x[SIZE]`	Hexadecimal, SIZE bytes per integer	`-t x2` = `-x`

Adding a z suffix to any type also displays printable characters at the end of each output line.

SIZE is a number. If TYPE is one of d, o, u or x, SIZE can also be specified with one of the following letters:

`C`	`sizeof(char)`
`S`	`sizeof(short)`
`I`	`sizeof(int)`
`L`	`sizeof(long)` or `sizeof(long double`)
`F`	`sizeof(float)`
`D`	`sizeof(double)`

nofBytes is a hexadecimal number, prefixed with 0x or 0X, and an optional multiplier suffix:

Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

$ printf "abc\ndef\ahi" | od -t x1

prints

0000000 61 62 63 0a 64 65 66 07 68 69
0000012

The x specifies to print hexadecimal values, the 1 following it specifies to print one hexadecimal value after another.

$ printf abc@def | od -t x1 -An
 61 62 63 40 64 65 66

od -t d4 --width=4   /path/to/file

Or a bit shorter:

od -i -w4            /path/to/file

Use z to also display printable characters:

od -t d4z --width=4  /path/to/file

The options -j (how many bytes to skip at the beginning) and -N (how many bytes to read) allow to specify a range that should be dumped:

od -j $startAtByte -N $countBytes $file

The format of the addresses (printed to the left) is specified with -A

It is

Print (zero indexed) bytes 16, 17, 18 and 19 from a given file:

$ od --skip-bytes=16 --read-bytes=4 --format=x1  --address-radix=n /tmp/foo/bar
0a 2b 2b e