Dump a file in various formats (POSIX)


od [-v] [-A format] [-t fmtstr] [-N count]
   [-j skip] [file]...

Runs on:

QNX Neutrino, Microsoft Windows


-A format
Display the file offset field in one of the following formats:
  • d — decimal, 9 digits
  • n — none (omit this field)
  • o — octal, 10 digits
  • x — hexadecimal, 7 digits

The default is o.

-j skip
Ignore the first skip bytes of data. You can add a trailing character to specify units of blocks (b), kilobytes (k), or megabytes (m).
-N count
Display only count bytes of input. You can add a trailing character to specify units of blocks (b), kilobytes (k), or megabytes (m).
-t format
Display data field using this format specification; see "Output formats," below.

The default format is oS.

Be verbose. If you don't specify the -v option, od folds multiple identical lines into a single line that contains an asterisk (*).
The pathname of an input file. If you don't specify any files, od reads from standard input.


Use the od utility to display a file in various forms, including decimal, hex, octal, and ASCII. The name "od" (octal dump) is derived from the default output format.

The od utility processes input in 16-byte units that are formatted into a line. In the default output format:

For example:

$ echo "abcdefghijklmnopqrstuvwxyz01234" | od
0000000000 14430661141 15031663145 15432665151 16033667155
0000000020 16434671161 17035673165 06114075171 01215031462

To exclude part of the input, use the -N and -j options. You can specify the arguments to these options in hex (using a 0x prefix) or octal (using a 0 prefix). The default units for these options are bytes, but you can specify different units as follows:

To specify: Add this suffix:
Blocks (512 bytes) b
Kilobytes (1024 bytes) k
Megabytes (1048576 bytes) m

Output formats

To specify the output format, use the -t option. The format argument—which you can specify in decimal, hex, or octal—tells od which format to use for presenting the output:

Named characters. Display printable characters as themselves, and nonprintable characters as a single dot (.).
Characters. Display printable characters as themselves; display all other characters as 2-digit hex values, except for the following:
ASCII mnemonic Value Representation
NUL 00 \0
<alert> 07 \a
<backspace> 08 \b
<tab> 09 \t
<newline> 0a \n
<vertical tab> 0b \v
<formfeed> 0c \f
<carriage return> 0d \r
Decimal, in objects the size of an int by default.
Floating point, in objects the size of an float by default.
Octal, in objects the size of an int by default.
Unsigned decimal, in objects the size of an int by default.
Hexadecimal, in objects the size of an int by default.

The input, processed in 16-byte units formatted into a line, is displayed according to the size you choose:

To display input as: Choose:
Sixteen 1-byte objects 1
Eight 2-byte objects 2
Four 4-byte values per line 4
Two 8-byte values per line 8
char C
double D
float F
int I
long or long double (depending on the format) L
short S


Display the second to eleventh sectors of the hard disk, /dev/hd0:

od -j 1b -N 10b /dev/hd0 

Exit status:

All input files were processed successfully.
An error occurred.