HD(1) INTERACTIVE UNIX System HD(1)
NAME
hd - display files in hexadecimal format
SYNOPSIS
hd [ -format [ -s offset ] [ -n count ] [ file ] ...
DESCRIPTION
The hd command displays the contents of files in hexade-
cimal, octal, decimal, and character formats. Control over
the specification of ranges of characters is also available.
The default behavior is with the following flags set: -abx
-A. This says that addresses (file offsets) and bytes are
printed in hexadecimal and that characters are also printed.
If no file argument is given, the standard input is read.
Options include:
-s offset Specify the beginning offset in the file where
printing is to begin. If no file argument is
given or if a seek fails because the input is a
pipe, offset bytes are read from the input and
discarded. Otherwise, a seek error will ter-
minate processing of the current file.
The offset may be given in decimal, hexadecimal
(preceded by 0x), or octal (preceded by a 0). It
is optionally followed by one of the following
multipliers: w, l, b, or k; for words (2 bytes),
long words (4 bytes), blocks (512 bytes), or K
bytes (1024 bytes). Note that this is the one
case where b does not stand for bytes. Since
specifying a hexadecimal offset in blocks would
result in an ambiguous trailing b, any offset
and multiplier may be separated by an asterisk
(*).
-n count Specify the number of bytes to process. The
count is in the same format as offset above.
FORMAT FLAGS
Format flags may specify addresses, characters, bytes, words
(2 bytes), or longs (4 bytes) to be printed in hexadecimal,
decimal, or octal. Two special formats may also be indi-
cated: text or ASCII. Format and base specifiers may be
freely combined and repeated as desired to specify different
bases (hexadecimal, decimal, or octal) for different output
formats (addresses, characters, etc.). All format flags
appearing in a single argument are applied as appropriate to
all other flags in that argument.
acbwlA
Output format specifiers for addresses, characters,
bytes, words, longs, and ASCII, respectively. Only one
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HD(1) INTERACTIVE UNIX System HD(1)
base specifier will be used for addresses; the address
will appear on the first line of output that begins
each new offset in the input.
The character format prints printable characters
unchanged special C escapes as defined in the language,
and remaining values in the specified base.
The ASCII format prints all printable characters
unchanged, and all others as a period (.). This format
appears to the right of the first of other specified
output formats. A base specifier has no meaning with
the ASCII format. If no other output format (other
than addresses) is given, bx is assumed. If no base
specifier is given, all of xdo are used.
xdo Output base specifiers for hexadecimal, decimal, and
octal. If no format specifier is given, all of acbwl
are used.
t Print a text file, each line preceded by the address in
the file. Normally, lines should be terminated by a \n
character, but long lines will be broken up. Control
characters in the range 0x00 to 0x1f are printed as
`^@' to `^_'. Bytes with the high bit set are preceded
by a tilde (~) and printed as if the high bit were not
set. The special characters (^, ~, \) are preceded by a
backslash (\) to escape their special meaning. As spe-
cial cases, two values are represented numerically as
`\177' and `\377'. This flag will override all output
format specifiers except addresses.
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