файлы дампа в различных форматах (dump files in various formats)
Расширенное описание (Extended description)
The od utility shall copy sequentially each input file to
standard output, transforming the input data according to the
output types specified by the -t option or the -bcdosx options.
If no output type is specified, the default output shall be as if
-t oS had been specified.
The number of bytes transformed by the output type specifier c
may be variable depending on the LC_CTYPE category.
The default number of bytes transformed by output type specifiers
d, f, o, u, and x corresponds to the various C-language types as
follows. If the c99 compiler is present on the system, these
specifiers shall correspond to the sizes used by default in that
compiler. Otherwise, these sizes may vary among systems that
conform to POSIX.1‐2008.
* For the type specifier characters d, o, u, and x, the default
number of bytes shall correspond to the size of the
underlying implementation's basic integer type. For these
specifier characters, the implementation shall support values
of the optional number of bytes to be converted corresponding
to the number of bytes in the C-language types char, short,
int, and long. These numbers can also be specified by an
application as the characters 'C', 'S', 'I', and 'L',
respectively. The implementation shall also support the
values 1, 2, 4, and 8, even if it provides no C-Language
types of those sizes. The implementation shall support the
decimal value corresponding to the C-language type long long.
The byte order used when interpreting numeric values is
implementation-defined, but shall correspond to the order in
which a constant of the corresponding type is stored in
memory on the system.
* For the type specifier character f, the default number of
bytes shall correspond to the number of bytes in the
underlying implementation's basic double precision floating-
point data type. The implementation shall support values of
the optional number of bytes to be converted corresponding to
the number of bytes in the C-language types float, double,
and long double. These numbers can also be specified by an
application as the characters 'F', 'D', and 'L',
respectively.
The type specifier character a specifies that bytes shall be
interpreted as named characters from the International Reference
Version (IRV) of the ISO/IEC 646:1991 standard. Only the least
significant seven bits of each byte shall be used for this type
specification. Bytes with the values listed in the following
table shall be written using the corresponding names for those
characters.
Table: Named Characters in od
┌─────────────┬──────────────┬───────────────────┬──────────────┐
│Value Name │ Value Name │ Value Name │ Value Name │
├─────────────┼──────────────┼───────────────────┼──────────────┤
│\000 nul │ \001 soh │ \002 stx │ \003 etx │
│\004 eot │ \005 enq │ \006 ack │ \007 bel │
│\010 bs │ \011 ht │ \012 lf or nl* │ \013 vt │
│\014 ff │ \015 cr │ \016 so │ \017 si │
│\020 dle │ \021 dc1 │ \022 dc2 │ \023 dc3 │
│\024 dc4 │ \025 nak │ \026 syn │ \027 etb │
│\030 can │ \031 em │ \032 sub │ \033 esc │
│\034 fs │ \035 gs │ \036 rs │ \037 us │
│\040 sp │ \177 del │ │ │
└─────────────┴──────────────┴───────────────────┴──────────────┘
Note: The "\012" value may be written either as lf or nl.
The type specifier character c specifies that bytes shall be
interpreted as characters specified by the current setting of the
LC_CTYPE locale category. Characters listed in the table in the
Base Definitions volume of POSIX.1‐2017, Chapter 5, File Format
Notation ('\\', '\a', '\b', '\f', '\n', '\r', '\t', '\v') shall
be written as the corresponding escape sequences, except that
<backslash> shall be written as a single <backslash> and a NUL
shall be written as '\0'. Other non-printable characters shall
be written as one three-digit octal number for each byte in the
character. Printable multi-byte characters shall be written in
the area corresponding to the first byte of the character; the
two-character sequence "**" shall be written in the area
corresponding to each remaining byte in the character, as an
indication that the character is continued. When either the -j
skip or -N count option is specified along with the c type
specifier, and this results in an attempt to start or finish in
the middle of a multi-byte character, the result is
implementation-defined.
The input data shall be manipulated in blocks, where a block is
defined as a multiple of the least common multiple of the number
of bytes transformed by the specified output types. If the least
common multiple is greater than 16, the results are unspecified.
Each input block shall be written as transformed by each output
type, one per written line, in the order that the output types
were specified. If the input block size is larger than the number
of bytes transformed by the output type, the output type shall
sequentially transform the parts of the input block, and the
output from each of the transformations shall be separated by one
or more <blank> characters.
If, as a result of the specification of the -N option or end-of-
file being reached on the last input file, input data only
partially satisfies an output type, the input shall be extended
sufficiently with null bytes to write the last byte of the input.
Unless -A n is specified, the first output line produced for each
input block shall be preceded by the input offset, cumulative
across input files, of the next byte to be written. The format of
the input offset is unspecified; however, it shall not contain
any <blank> characters, shall start at the first character of the
output line, and shall be followed by one or more <blank>
characters. In addition, the offset of the byte following the
last byte written shall be written after all the input data has
been processed, but shall not be followed by any <blank>
characters.
If no -A option is specified, the input offset base is
unspecified.
