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33 .Nd ASCII, decimal, hexadecimal, octal dump
37 .Op Fl e Ar format_string
38 .Op Fl f Ar format_file
46 .Op Fl e Ar format_string
47 .Op Fl f Ar format_file
56 utility is a filter which displays the specified files, or
57 the standard input, if no files are specified, in a user specified
60 The options are as follows:
61 .Bl -tag -width indent
63 .Em One-byte octal display .
64 Display the input offset in hexadecimal, followed by sixteen
65 space-separated, three column, zero-filled, bytes of input data,
68 .Em One-byte character display .
69 Display the input offset in hexadecimal, followed by sixteen
70 space-separated, three column, space-filled, characters of input
73 .Em Canonical hex+ASCII display .
74 Display the input offset in hexadecimal, followed by sixteen
75 space-separated, two column, hexadecimal bytes, followed by the
76 same sixteen bytes in %_p format enclosed in ``|'' characters.
82 .Em Two-byte decimal display .
83 Display the input offset in hexadecimal, followed by eight
84 space-separated, five column, zero-filled, two-byte units
85 of input data, in unsigned decimal, per line.
86 .It Fl e Ar format_string
87 Specify a format string to be used for displaying data.
88 .It Fl f Ar format_file
89 Specify a file that contains one or more newline separated format strings.
90 Empty lines and lines whose first non-blank character is a hash mark
98 .Em Two-byte octal display .
99 Display the input offset in hexadecimal, followed by eight
100 space-separated, six column, zero-filled, two byte quantities of
101 input data, in octal, per line.
105 bytes from the beginning of the input.
108 is interpreted as a decimal number.
114 is interpreted as a hexadecimal number,
115 otherwise, with a leading
118 is interpreted as an octal number.
119 Appending the character
126 causes it to be interpreted as a multiple of
135 to display all input data.
138 option, any number of groups of output lines, which would be
139 identical to the immediately preceding group of output lines (except
140 for the input offsets), are replaced with a line comprised of a
143 .Em Two-byte hexadecimal display .
144 Display the input offset in hexadecimal, followed by eight, space
145 separated, four column, zero-filled, two-byte quantities of input
146 data, in hexadecimal, per line.
151 sequentially copies the input to standard output, transforming the
152 data according to the format strings specified by the
156 options, in the order that they were specified.
158 A format string contains any number of format units, separated by
160 A format unit contains up to three items: an iteration count, a byte
163 The iteration count is an optional positive integer, which defaults to
165 Each format is applied iteration count times.
167 The byte count is an optional positive integer.
168 If specified it defines the number of bytes to be interpreted by
169 each iteration of the format.
171 If an iteration count and/or a byte count is specified, a single slash
172 must be placed after the iteration count and/or before the byte count
173 to disambiguate them.
174 Any whitespace before or after the slash is ignored.
176 The format is required and must be surrounded by double quote
178 It is interpreted as a fprintf-style format string (see
181 following exceptions:
182 .Bl -bullet -offset indent
184 An asterisk (*) may not be used as a field width or precision.
186 A byte count or field precision
188 required for each ``s'' conversion
189 character (unlike the
191 default which prints the entire string if the precision is unspecified).
193 The conversion characters ``h'', ``l'', ``n'', ``p'' and ``q'' are
196 The single character escape sequences
197 described in the C standard are supported:
198 .Bd -ragged -offset indent -compact
199 .Bl -column <alert_character>
201 .It "<alert character> \ea"
202 .It "<backspace> \eb"
203 .It "<form-feed> \ef"
205 .It "<carriage return> \er"
207 .It "<vertical tab> \ev"
214 utility also supports the following additional conversion strings:
216 .It Cm \&_a Ns Op Cm dox
217 Display the input offset, cumulative across input files, of the
218 next byte to be displayed.
219 The appended characters
224 specify the display base
225 as decimal, octal or hexadecimal respectively.
226 .It Cm \&_A Ns Op Cm dox
229 conversion string except that it is only performed
230 once, when all of the input data has been processed.
232 Output characters in the default character set.
233 Nonprinting characters are displayed in three character, zero-padded
234 octal, except for those representable by standard escape notation
236 which are displayed as two character strings.
238 Output characters in the default character set.
239 Nonprinting characters are displayed as a single
243 characters, with the exception that control characters are
244 displayed using the following, lower-case, names.
245 Characters greater than 0xff, hexadecimal, are displayed as hexadecimal
247 .Bl -column 000_nu 001_so 002_st 003_et 004_eo
248 .It "000 NUL" Ta "001 SOH" Ta "002 STX" Ta "003 ETX" Ta "004 EOT" Ta "005 ENQ"
249 .It "006 ACK" Ta "007 BEL" Ta "008 BS" Ta "009 HT" Ta "00A LF" Ta "00B VT"
250 .It "00C FF" Ta "00D CR" Ta "00E\ SO" Ta "00F SI" Ta "010 DLE" Ta "011 DC1"
251 .It "012 DC2" Ta "013 DC3" Ta "014 DC4" Ta "015\ NAK" Ta "016 SYN" Ta "017 ETB"
252 .It "018 CAN" Ta "019 EM" Ta "01A SUB" Ta "01B ESC" Ta "01C FS" Ta "01D GS"
253 .It "01E RS" Ta "01F US" Ta "07F DEL" Ta \& Ta \& Ta \&
257 The default and supported byte counts for the conversion characters
259 .Bl -tag -width "Xc,_Xc,_Xc,_Xc,_Xc,_Xc" -offset indent
260 .It Li \&%_c , \&%_p , \&%_u , \&%c
261 One byte counts only.
263 .Li \&%d , \&%i , \&%o ,
264 .Li \&%u , \&%X , \&%x
266 Four byte default, one, two and four byte counts supported.
268 .Li \&%E , \&%e , \&%f ,
271 Eight byte default, four and twelve byte counts supported.
274 The amount of data interpreted by each format string is the sum of the
275 data required by each format unit, which is the iteration count times the
276 byte count, or the iteration count times the number of bytes required by
277 the format if the byte count is not specified.
279 The input is manipulated in ``blocks'', where a block is defined as the
280 largest amount of data specified by any format string.
281 Format strings interpreting less than an input block's worth of data,
282 whose last format unit both interprets some number of bytes and does
283 not have a specified iteration count, have the iteration count
284 incremented until the entire input block has been processed or there
285 is not enough data remaining in the block to satisfy the format string.
287 If, either as a result of user specification or
290 the iteration count as described above, an iteration count is
291 greater than one, no trailing whitespace characters are output
292 during the last iteration.
294 It is an error to specify a byte count as well as multiple conversion
295 characters or strings unless all but one of the conversion characters
301 If, as a result of the specification of the
303 option or end-of-file being reached, input data only partially
304 satisfies a format string, the input block is zero-padded sufficiently
305 to display all available data (i.e., any format units overlapping the
306 end of data will display some number of the zero bytes).
308 Further output by such format strings is replaced by an equivalent
310 An equivalent number of spaces is defined as the number of spaces
313 conversion character with the same field width
314 and precision as the original conversion character or conversion
319 conversion flag characters
320 removed, and referencing a NULL string.
322 If no format strings are specified, the default display is equivalent
329 Dump input in canonical (hex+ASCII) form:
330 .Bd -literal -offset indent
331 $ echo "FreeBSD: The power to serve" | hexdump -C
332 00000000 46 72 65 65 42 53 44 3a 20 54 68 65 20 70 6f 77 |FreeBSD: The pow|
333 00000010 65 72 20 74 6f 20 73 65 72 76 65 0a |er to serve.|
337 Same as above but skipping the first 4 bytes of stdin and interpreting only 3
339 .Bd -literal -offset indent
340 $ echo "FreeBSD: The power to serve" | hexdump -C -s 4 -n 3
341 00000004 42 53 44 |BSD|
345 Assuming a format file named
347 with the following contents that specify a perusal format:
348 .Bd -literal -offset indent
349 "%06.6_ao " 12/1 "%3_u "
354 Dump input in canonical form using the format in
356 .Bd -literal -offset indent
357 $ echo "FreeBSD" | hexdump -f format.txt -C
358 000000 F r e e B S D lf F r e e B S D .
359 00000000 46 72 65 65 42 53 44 0a |FreeBSD.|
363 Assuming a format file named
365 with the following contents that simulate the
368 .Bd -literal -offset indent
370 "%07.7_ax " 8/2 "%04x " "\en"
373 Dump input in canonical form using the format in
375 .Bd -literal -offset indent
376 $ echo "FreeBSD: The power to serve" | hexdump -f format.txt -C
377 0000000 7246 6565 5342 3a44 5420 6568 7020 776f
378 00000000 46 72 65 65 42 53 44 3a 20 54 68 65 20 70 6f 77 |FreeBSD: The pow|
379 0000010 7265 7420 206f 6573 7672 0a65
380 00000010 65 72 20 74 6f 20 73 65 72 76 65 0a |er to serve.|