hexdump
, hd ASCII, decimal, hexadecimal, octal dump
see also :
gdb - od
Synopsis
hexdump
[-bcCdovx]
[-e format_string]
[-f format_file]
[-n length]
[-s skip] file ...
hd [-bcdovx]
[-e format_string]
[-f format_file]
[-n length]
[-s skip] file ...
add an example, a script, a trick and tips
examples
Display the input in perusal format:
"%06.6_ao " 12/1 "%3_u "
"\t\t" "%_p "
"\n"
Implement the -x option:
"%07.7_Ax\n"
"%07.7_ax " 8/2 "%04x " "\n"
Some examples for the -e option:
# hex bytes
% echo hello | hexdump -v -e ’/1 "%02X "’ ; echo
68 65 6C 6C 6F 0A
# same, with ASCII section
% echo hello | hexdump -e ’8/1 "%02X ""\t"" "’ -e ’8/1
"%c""\n"’
68 65 6C 6C 6F 0A hello
# hex with preceding ’x’
% echo hello | hexdump -v -e ’"x" 1/1 "%02X" " "’ ; echo
x68 x65 x6C x6C x6F x0A
# one hex byte per line
% echo hello | hexdump -v -e ’/1 "%02X\n"’
68
65
6C
6C
6F
0A
# a table of byte#, hex, decimal, octal, ASCII
% echo hello | hexdump -v -e ’/1 "%_ad# "’ -e ’/1 "%02X hex"’ -e
’/1 " = %03i dec"’ -e ’/1 " = %03o oct"’ -e ’/1 " = _%c\_\n"’
0# 68 hex = 104 dec = 150 oct = _h_
1# 65 hex = 101 dec = 145 oct = _e_
2# 6C hex = 108 dec = 154 oct = _l_
3# 6C hex = 108 dec = 154 oct = _l_
4# 6F hex = 111 dec = 157 oct = _o_
5# 0A hex = 010 dec = 012 oct = _
_
# byte# & ASCII with control chars
% echo hello | hexdump -v -e ’/1 "%_ad# "’ -e ’/1 "
_%_u\_\n"’
0# _h_
1# _e_
2# _l_
3# _l_
4# _o_
5# _lf_
source
diff <(hexdump -C $1 ) <(hexdump -C $2
)
source
Is there a utility like hexdump that will handle non-native endian-ness?
Is there a utility like hexdump that will handle non-native
endian-ness?
Yes, the utility is called Perl.
Well actually Data::HexDumper - though you could roll
your own.
number_format
A string specifying how to format the data. It can be any of the following,
which you will notice have the same meanings as they do to perl's pack function:
C - unsigned char
S - unsigned 16-bit, native endianness
v or S< - unsigned 16-bit, little-endian
n or S> - unsigned 16-bit, big-endian
L - unsigned 32-bit, native endianness
V or L< - unsigned 32-bit, little-endian
N or L> - unsigned 32-bit, big-endian
Q - unsigned 64-bit, native endianness
Q< - unsigned 64-bit, little-endian
Q> - unsigned 64-bit, big-endian
source
How to convert data to plain hex from console
hexdump -e '"%x"'
xxd -p | tr -d '\n'
If you get tired of writing this every time, create an
alias.
source
What does an asterisk "*" mean in hexdump output?
As per request: A line in the hexdump output consisting just a
* means same as the line above. This is
mentioned in the hexdump's manpage at the -v option
(easy to be overlooked).
source
hexdump vs xxd format difference
There's no one command that I know of that will do the
conversion, but it can easily be broken up into a few steps:
- Strip addresses from
hexdump output using
sed
- Convert into binary using
xxd
- Endian conversion (for example,
5a42 becomes
425a) using dd
Here's the full command:
sed 's/^[0-9]*//' hexdump | xxd -r -p | dd conv=swab of=binaryfile
description
The hexdump utility is a
filter which displays the specified files, or the standard
input, if no files are specified, in a user specified
format.
The options are
as follows:
-b
One-byte
octal display. Display the input offset in hexadecimal,
followed by sixteen space-separated, three column,
zero-filled, bytes of input data, in octal, per line.
-c
One-byte
character display. Display the input offset in
hexadecimal, followed by sixteen space-separated, three
column, space-filled, characters of input data per line.
-C
Canonical
hex+ASCII display. Display the input offset in
hexadecimal, followed by sixteen space-separated, two
column, hexadecimal bytes, followed by the same sixteen
bytes in %_p format enclosed in
’’|’’ characters.
Calling the
command hd implies this option.
-d
Two-byte
decimal display. Display the input offset in
hexadecimal, followed by eight space-separated, five column,
zero-filled, two-byte units of input data, in unsigned
decimal, per line.
-e
format_string
Specify a format string to be
used for displaying data.
-f
format_file
Specify a file that contains
one or more newline separated format strings. Empty lines
and lines whose first non-blank character is a hash mark
(#) are ignored.
-n
length
Interpret only length
bytes of input.
-o
Two-byte
octal display. Display the input offset in hexadecimal,
followed by eight space-separated, six column, zero-filled,
two byte quantities of input data, in octal, per line.
-s
offset
Skip offset bytes from
the beginning of the input. By default, offset is
interpreted as a decimal number. With a leading 0x or
0X, offset is interpreted as a hexadecimal
number, otherwise, with a leading 0, offset is
interpreted as an octal number. Appending the character
b, k, or m to offset causes it
to be interpreted as a multiple of 512, 1024, or 1048576,
respectively.
-v
Cause
hexdump to display all input data. Without the
-v option, any number of groups of output
lines, which would be identical to the immediately preceding
group of output lines (except for the input offsets), are
replaced with a line comprised of a single asterisk.
-x
Two-byte
hexadecimal display. Display the input offset in
hexadecimal, followed by eight, space separated, four
column, zero-filled, two-byte quantities of input data, in
hexadecimal, per line.
For each input
file, hexdump sequentially copies the input to
standard output, transforming the data according to the
format strings specified by the -e and
-f options, in the order that they were
specified.
Formats
A format string contains any number of format units,
separated by whitespace. A format unit contains up to three
items: an iteration count, a byte count, and a format.
The iteration
count is an optional positive integer, which defaults to
one. Each format is applied iteration count times.
The byte count
is an optional positive integer. If specified it defines the
number of bytes to be interpreted by each iteration of the
format.
If an iteration
count and/or a byte count is specified, a single slash must
be placed after the iteration count and/or before the byte
count to disambiguate them. Any whitespace before or after
the slash is ignored.
The format is
required and must be surrounded by double quote ("
") marks. It is interpreted as a fprintf-style format
string (see fprintf(3)), with the following exceptions:
•
An asterisk (*) may not be used
as a field width or precision.
•
A byte count or field precision
is required for each ’’s’’
conversion character (unlike the fprintf(3) default which
prints the entire string if the precision is
unspecified).
•
The conversion characters
’’%’’,
’’h’’,
’’l’’,
’’n’’, ’’p’’
and ’’q’’ are not supported.
•
The single character escape
sequences described in the C standard are supported:
NUL \0
<alert character> \a
<backspace> \b
<form-feed> \f
<newline> \n
<carriage return> \r
<tab> \t
<vertical tab> \v
The
hexdump utility also supports the following
additional conversion strings:
_a[dox]
Display the
input offset, cumulative across input files, of the next
byte to be displayed. The appended characters d,
o, and x specify the display base as decimal,
octal or hexadecimal respectively.
_A[dox]
Identical to
the _a conversion string except that it is only
performed once, when all of the input data has been
processed.
_c
Output
characters in the default character set. Nonprinting
characters are displayed in three character, zero-padded
octal, except for those representable by standard escape
notation (see above), which are displayed as two character
strings.
_p
Output
characters in the default character set. Nonprinting
characters are displayed as a single
’’.’’.
_u
Output US ASCII
characters, with the exception that control characters are
displayed using the following, lower-case, names. Characters
greater than 0xff, hexadecimal, are displayed as hexadecimal
strings.
000 NUL
001 SOH 002 STX 003 ETX 004 EOT
005 ENQ
006 ACK 007 BEL 008 BS 009 HT
00A LF 00B VT
00C FF 00D CR 00E SO 00F SI 010 DLE
011 DC1
012 DC2 013 DC3 014 DC4 015 NAK
016 SYN 017 ETB
018 CAN 019 EM 01A SUB 01B ESC
01C FS 01D GS
01E RS 01F US 07F DEL
The default and
supported byte counts for the conversion characters are as
follows:
%_c, %_p, %_u, %c
One byte counts
only.
%d, %i, %o, %u, %X, %x
Four byte
default, one, two and four byte counts supported.
%E, %e, %f, %G, %g
Eight byte
default, four and twelve byte counts supported.
The amount of
data interpreted by each format string is the sum of the
data required by each format unit, which is the iteration
count times the byte count, or the iteration count times the
number of bytes required by the format if the byte count is
not specified.
The input is
manipulated in ’’blocks’’, where a
block is defined as the largest amount of data specified by
any format string. Format strings interpreting less than an
input block’s worth of data, whose last format unit
both interprets some number of bytes and does not have a
specified iteration count, have the iteration count
incremented until the entire input block has been processed
or there is not enough data remaining in the block to
satisfy the format string.
If, either as a
result of user specification or hexdump modifying the
iteration count as described above, an iteration count is
greater than one, no trailing whitespace characters are
output during the last iteration.
It is an error
to specify a byte count as well as multiple conversion
characters or strings unless all but one of the conversion
characters or strings is _a or _A.
If, as a result
of the specification of the -n option or
end-of-file being reached, input data only partially
satisfies a format string, the input block is zero-padded
sufficiently to display all available data (i.e., any format
units overlapping the end of data will display some number
of the zero bytes).
Further output
by such format strings is replaced by an equivalent number
of spaces. An equivalent number of spaces is defined as the
number of spaces output by an s conversion character
with the same field width and precision as the original
conversion character or conversion string but with any
’’+’’,
’’ ’’,
’’#’’ conversion flag characters
removed, and referencing a NULL string.
If no format
strings are specified, the default display is equivalent to
specifying the -x option.
exit status
The hexdump and hd utilities exit 0 on
success, and >0 if an error occurs.
see also
gdb , od
BSD
February 18, 2010 BSD