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od(1)
NAME
od - Writes the contents of a file to standard output
SYNOPSIS
od [-v] [-Q] [-A address_base] [-j skip] [-N count] [-t type_string...]
[file...]
od [-abBcCdDefFhHiIlLoOpPSvxX] [-s[number]] [-w[number]] [file...] [+]
[offset] [.] [b | B] [label] [.] [b | B]
The od command reads file (standard input by default), and writes the
information stored in file to standard output using the format specified by
the first option. If you do not specify the first option, the -o option is
the default.
STANDARDS
Interfaces documented on this reference page conform to industry standards
as follows:
od: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
Format characters are as follows:
-Q [Tru64 UNIX] Displays quadwords as hexadecimal values. This option
applies only to the operating system for Alpha AXP systems.
-a [Tru64 UNIX] Displays bytes as characters and displays them with their
ASCII names. If the p character is also given, bytes with even parity
are underlined. The P character causes bytes with odd parity to be
underlined. Otherwise, parity is ignored.
-A address_base
Specifies the input offset base with the single-character address_base
argument. The characters d, o, and x specify that the offset base be
written in decimal, octal, or hexadecimal, respectively. The character
n specifies that the offset not be written at all.
-b Displays bytes as octal values.
-B [Tru64 UNIX] Displays short words as octal values.
-c Displays bytes as characters using the current setting of the LC_CTYPE
variable. The following nongraphic characters appear as C escape
sequences:
\0 Null
\a [Tru64 UNIX] Alarm (or bell)
\b Backspace
\f Formfeed
\n Newline character
\r Enter
\t Tab
\v [Tru64 UNIX] Vertical tab
Other nongraphic characters appear as 3-digit octal numbers. Bytes with
the parity bit set are displayed in octal.
-C [Tru64 UNIX] Displays any extended characters as standard printable
ASCII characters using the appropriate character escape string.
-d Displays short words as unsigned decimal values.
-D [Tru64 UNIX] Displays long words as unsigned decimal values.
-e [Tru64 UNIX] Displays long words as double-precision, floating-point.
(Same as -F.)
-f [Tru64 UNIX] Displays long words as single-precision, floating-point.
-F [Tru64 UNIX] Displays long words as double-precision, floating-point.
-h [Tru64 UNIX] Displays short words as unsigned hexadecimal values.
-H [Tru64 UNIX] Displays long words as unsigned hexadecimal values.
-i [Tru64 UNIX] Displays short words as signed decimal values.
-I, -l, -L
[Tru64 UNIX] Display long words as signed decimal values. (The three
options are identical.)
-j skip
Jumps over (reading or seeking) skip bytes from the beginning of the
concatenated input files. If the input is not at least skip bytes
long, od writes a diagnostic message to standard error and returns a
nonzero exit value.
The skip argument is interpreted as a decimal number by default. If
you include a leading offset of 0x or 0X, skip is interpreted as a
hexadecimal number. A leading offset of 0 (zero) causes skip to be
interpreted as an octal number.
If you append the character b, k, or m to skip, the number is
interpreted as a multiple of 512, 1024, or 1,048,576 bytes,
respectively. If b is appended to a skip interpreted as hexadecimal,
it is recognized as the last digit of the skip, not a block indicator.
-N count
Causes od to format no more than count bytes of input.
The count argument is interpreted as a decimal number by default. If
you include a leading offset of 0x or 0X, count is interpreted as a
hexadecimal number. A leading offset of 0 (zero) causes count to be
interpreted as an octal number. If there are not count bytes of input
available (after successfully skipping bytes as specified by -j), od
formats the available input.
-o Displays short words as octal values.
-O [Tru64 UNIX] Displays long words as unsigned octal values.
-p [Tru64 UNIX] Indicates even parity on -a conversion.
-P [Tru64 UNIX] Indicates odd parity on -a conversion.
-s[number]
[Tru64 UNIX] Looks for strings of ASCII graphic characters, terminated
with a null byte. The number argument specifies the minimum length
string to be recognized. By default, the minimum length is 3
characters. Allowable characters are those between blank (040) and
tilde (0176), as well as backspace, tab, linefeed, formfeed, and
carriage-return (010 through 015, except 013).
-s If the environment variable CMD_ENV is set to svr4, displays signed
words (32-bit or Tru64 UNIX short words) as signed decimal values.
[Tru64 UNIX] If the environment variable CMD_ENV is set to xpg4,
action is the same as using the -i option.
-S [Tru64 UNIX] Displays long words as signed decimal values.
-t type_string...
Specifies one or more output types. The type_string argument is a
string that specifies the types to be used when writing the input data.
The type_string argument consists of the following type specification
characters:
a Named character
c Character
d Signed decimal
f Floating point
o Octal
u Unsigned decimal
x Hexadecimal
The type specification characters d, f, o, u, and x can be followed by
an optional unsigned decimal integer that specifies the number of bytes
to be transformed by each instance of the output type.
The type specification character f can be followed by one of the
following optional characters, which indicate the type of the item to
which the conversion should be applied.
F float
D double
L long double
The type specification characters d, o, u, and x can be followed by one
of the following optional characters, which indicate the type of the
item to which the conversion should be applied:
C char
I int
L long
S short
You can concatenate multiple types within the same type_string argument
and you can specify multiple -t arguments. The od command writes the
output lines for each type specified in the order in which you entered
the type specification characters.
-v Shows all data. By default, display lines that are identical to the
previous line are not output (except for the byte offsets), but are
indicated with an * (asterisk) in column 1.
-w[number]
[Tru64 UNIX] Specifies the number of input bytes to be interpreted and
displayed on each output line. If -w is not specified, 16 bytes are
read for each display line. If number is not specified, it defaults to
32.
-x Displays short words as unsigned hexadecimal values. (Same as -h.)
-X [Tru64 UNIX] Displays long words as unsigned hexadecimal values.
(Same as -H.)
[Tru64 UNIX] An uppercase format character implies the long or double-
precision form of the object.
OPERANDS
file
A path name of a file to be written. If no file operands are
specified, the standard input will be used. If the first character of
file is a plus sign (+) or the first character of the first file
operand is numeric, no more than two operands are given, and none of
the -A, -j, -N, or -t options is specified, the operand is assumed to
be an offset.
offset
Specifies the point in the file at which the output starts. The offset
argument is interpreted as octal bytes. If a . (dot) is added to
offset, it is interpreted in decimal. If offset begins with x or 0x,
it is interpreted in hexadecimal. If b (B) is appended to a
nonhexadecimal offset, the offset is interpreted as a block count,
where a block is 512 (1024) bytes. If b (B) is appended to a
hexadecimal offset, the b (B) is interpreted as part of the offset and
the offset is not interpreted as a block count; a block count can be
specified only with a decimal or an octal offset.
label
Interpreted as a pseudoaddress for the first byte displayed. It is
shown in parentheses following the file offset. It is intended to be
used with core images to indicate the real memory address. The syntax
for label is identical to that for offset.
DESCRIPTION
The output continues until the end of the file.
When od reads standard input, the offset and label operands must be
preceded by a + (plus sign).
If you omit the file argument and do not specify -A, -j, -N, or -t, you
must precede the offset argument by a + (plus sign) character.
To be sure that od assumes the argument to be an offset:
· Make the first character of file a + sign, or the first character of
the first file argument numeric.
· Give no more than two arguments.
· Specify none of the -A, -j, -N, or -t options.
RESTRICTIONS
The od command has the following restrictions:
· You cannot use the command with disks that have a capacity of more
than 4 GB.
· You cannot specify an offset of more than (2**32)-1 as a starting
point.
NOTES
[Tru64 UNIX] The -i option displays short words as signed decimal values.
The -i option used to be -s in System V.
EXIT STATUS
The following exit values are returned:
0 All input files were processed successfully.
>0 An error occurred.
EXAMPLES
1. To display a file in octal word format, a page at a time, enter:
od a.out | more
2. To translate a file into several formats at once, enter:
od -cx a.out >a.xcd
This writes a.out in hexadecimal format (the -x option) into the file
a.xcd, giving also the ASCII character equivalent, if any, of each
byte (the -c option).
3. To start in the middle of a file, enter:
od -bcx a.out +100.
This displays a.out in octal-byte, character, and hexadecimal formats,
starting from the 100th byte. The . (dot) after the offset makes it a
decimal number. Without the . (dot), the dump starts from the 64th
(100 octal) byte.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of od:
LANG
Provides a default value for the internationalization variables that
are unset or null. If LANG is unset or null, the corresponding value
from the default locale is used. If any of the internationalization
variables contain an invalid setting, the utility behaves as if none of
the variables had been defined.
LC_ALL
If set to a non-empty string value, overrides the values of all the
other internationalization variables.
LC_CTYPE
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to
multibyte characters in arguments).
LC_MESSAGES
Determines the locale for the format and contents of diagnostic
messages written to standard error.
NLSPATH
Determines the location of message catalogues for the processing of
LC_MESSAGES.
SEE ALSO
Commands: sed(1)
Files: locale(4)
Standards: standards(5)
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