od (host)
Dump a file in various formats (POSIX)
Syntax:
od [-v] [-A format] [-t fmtstr] [-N count]
[-j skip] [file]...
Runs on:
Microsoft Windows
Options:
- -A format
- Display the file offset field in one of the following formats:
d
— decimal, 9 digitsn
— none (omit this field)o
— octal, 10 digitsx
— 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.
- -v
- Be verbose.
If you don't specify the -v option, od folds
multiple identical lines into a single line that contains an asterisk (
*
). - file
- The pathname of an input file. If you don't specify any files, od reads from standard input.
Description:
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:
- the file offset field is displayed in octal, 10 digits
- a space separates the file offset field from the data
- the data is displayed as four space-separated objects in octal
For example:
$ echo "abcdefghijklmnopqrstuvwxyz01234" | od
0000000000 14430661141 15031663145 15432665151 16033667155
0000000020 16434671161 17035673165 06114075171 01215031462
0000000040
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:
- a
- Named characters.
Display printable characters as themselves, and nonprintable characters as a single dot (
.
). - c
- 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 - d[1|2|4|C|S|I|L]
- Decimal, in objects the size of an int by default.
- f[4|8|F|D|L]
- Floating point, in objects the size of an float by default.
- o[1|2|4|C|S|I|L]
- Octal, in objects the size of an int by default.
- u[1|2|4|C|S|I|L]
- Unsigned decimal, in objects the size of an int by default.
- x[1|2|4|C|S|I|L]
- 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 |
Examples:
Display the second to eleventh sectors of the hard disk, /dev/hd0:
od -j 1b -N 10b /dev/hd0
Exit status:
- 0
- All input files were processed successfully.
- >0
- An error occurred.