od(1)
NAME
od, xd − octal and hexadecimal dump
SYNOPSIS
od [-v] [-A address_base] [-j skip] [-N count] [-t type_string] ... [file ...]
xd [-v] [-A address_base] [-j skip] [-N count] [-t type_string] ... [file ...]
The following pre- POSIX usage is also supported.
od [-bcdosx] [file] [[+][0x] offset [.][b]]
xd [-bcdosx] [file] [[+][0x] offset [.][b]]
DESCRIPTION
od and C xd concatenate one or more input files and write their contents to standard output in a user-specified format. If file is not specified, the standard input is used.
Options and Arguments
od and xd recognize the following options and command-line arguments:
-A address_base Specify the input offset base. address_base is a single character that defines which format the offset base is written in:
d Decimal format.
o Octal format.
x Hexadecimal format.
n Do not write the offset.
-j skip Jump over skip bytes from the beginning of the input. od seeks past the first skip bytes in the concatenated input files. If the combined input is not at least skip bytes long, od writes a diagnostic message to standard error and exits with a non-zero exit status. By default, skip is interpreted as a decimal number. If skip has a leading 0x or 0X, it is interpreted as a hexadecimal number; a leading 0 indicates that skip is an octal number.
If the value of skip is followed by a b, k, or m, it is interpreted as a multiple of 512, 1024, or 1048576, respectively.
-N count Format no more than count bytes of input.
By default, count is interpreted as a decimal number. A leading 0x or 0X indicates that count is a hexadecimal number; a leading 0 identifies an octal value.
If count bytes of input are not available (after successfully skipping if -jskip is specified), the input that is available is formatted.
-t type_string type_string is a string defining the types to be used when writing the input data.
The string can contain any of the following type-specification characters:
a named character ,
c character ,
d signed decimal ,
f floating point ,
o octal ,
u unsigned decimal ,
x hexadecimal ,
Type specification characters d, f, o, u, and x can be followed by an optional unsigned decimal integer specifying the number of bytes to be transformed by each instance of the output type, or by an optional C, S, I, or L indicating that the conversion should be applied to an item of type char, short, int, or long, respectively.
Type specification character f can be followed by an optional F, D, or L indicating that the conversion should be applied to an item of type float, double, or long double, respectively.
Multiple types can be concatenated within the same type_string and multiple -t options can be specified. Output lines are written for each type specified in the order in which the type specification characters appear.
-v Write all input data. Without the -v option, any number of groups of output lines, that would be identical to the immediately preceding group of output lines (except for the byte offsets), are replaced with a line containing only an asterisk (*).
file Pathname of one or more input files to be processed. If file is not specified, the standard input is used.
Input files can be any file type.
DESCRIPTION OF PRE-POSIX USAGE
od and xd dump file in one or more formats as selected by the first argument. If the first argument is missing, the default is -o for od; -x for xd. An offset field is inserted at the beginning of each line. For od, the offset is in octal, for xd, the offset is in hexadecimal.
Options
od and xd recognize the following format options:
-b Interpret bytes in octal (hexadecimal).
-c Interpret bytes in ASCII. Certain non-graphic characters appear as C escapes: null=\0, backspace=\b, form-feed=\f, new-line=\n, return=\r, tab=\t; others appear as 3-digit octal numbers.
-d Interpret 16-bit words in decimal.
-o Interpret 16-bit words in octal.
-s Interpret 16-bit words in signed decimal.
-x Interpret 16-bit words in hexadecimal.
file specifies which file is to be dumped. If file is not specified, the standard input is used.
offset specifies the offset in the file where dumping is to commence, and is normally interpreted as octal bytes. Interpretation can be altered as follows:
• offset must be preceded by + if the file argument is omitted.
• offset preceded by 0x is interpreted in hexadecimal.
• offset followed by . is interpreted in decimal.
• offset followed by b is interpreted in blocks of 512 bytes.
Dumping continues until end-of-file.
EXAMPLES
Write hexadecimal bytes and the corresponding octal values to the standard output in blocks of 16 bytes in one line, by transforming the data from the input file file1:
od -tx1oC file1
The following commands write one line each of the types character, signed decimal integer, and float, in the order given, transforming 100 bytes of data starting from fifteenth byte offset in the file file1:
od -j14 -N100 -tc -tdfF file1
od -j0xe -N100 -tcd4fF file1
Write one line each of the types unsigned integer, named character, and long double, with the offsets written in hexadecimal and forcing a write, even on lines that are identical to the immediately preceding group of output lines:
od -v -Ax -tuafL file1
WARNINGS
When the output format is of floating-point type; i.e., when using the -t fD, -t fL, or -t f options:
• If the input bytes cannot be transformed into a valid floating point number, a floating point exception might occur. In that case, the output is printed as a string containing some non-numeric characters and program execution continues.
• When the number of input bytes used for transformation is set to 1 with the type specifier characters d, o, u, or x, only the least-significant seven bits of each byte are used.
• When one or more of the -A, -j, -N, or -t options is specified, an operand starting with the first character as a plus-sign (+) or the first character as numeric is interpreted as a file name.
EXTERNAL INFLUENCES
Environment Variables
LC_CTYPE determines the range of printable characters.
LANG determines the language in which messages are displayed.
If LC_CTYPE is not specified in the environment or is set to the empty string, the value of LANG is used as a default for each unspecified or empty variable. If LANG is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG. If any internationalization variable contains an invalid setting, od behaves as if all internationalization variables are set to "C". See environ(5).
International Code Set Support
Single- and multi-byte character code sets are supported. Multi-byte data is displayed as multi-byte values.
RETURN VALUE
Exit values are:
0 Successful completion.
>0 Error condition occured.
SEE ALSO
STANDARDS CONFORMANCE
od: SVID2, XPG2, XPG3
Hewlett-Packard Company — HP-UX Release 9.03: April 1994