dc3dd man page

dc3dd — convert and copy a file

Description

------ usage: ------

dc3dd [OPTION 1] [OPTION 2] ... [OPTION N]

*or*

dc3dd [HELP OPTION]

where each OPTION is selected from the basic or advanced options listed below, or HELP OPTION is selected from the help options listed below.

-------------- basic options: --------------

if=DEVICE or FILE

Read input from a device or a file (see note #1 below for how to read from standard input). This option can only be used once and cannot be combined with ifs=, pat=, or tpat=.

ifs=BASE.FMT

Read input from a set of files with base name BASE and sequential file name extensions conforming to the format specifier FMT (see note #4 below for how to specify FMT). This option can only be used once and cannot be combined with if=, pat=, or tpat=.

of=FILE or DEVICE

Write output to a file or device (see note #2 below for how to write to standard output). This option can be used more than once (see note #3 below for how to generate multiple outputs).

hof=FILE or DEVICE

Write output to a file or device, hash the output bytes, and verify by comparing the output hash(es) to the input hash(es). This option can be used more than once (see note #3 below for how to generate multiple outputs).

ofs=BASE.FMT

Write output to a set of files with base name BASE and sequential file name extensions generated from the format specifier FMT (see note #4 below for how to specify FMT). This option can be used more than once (see note #3 below for how to generate multiple outputs). Specify the maximum size of each file in the set using ofsz=.

hofs=BASE.FMT

Write output to a set of files with base name BASE and sequential file name extensions generated from the format specifier FMT (see note #4 below for how to specify FMT). Hash the output files and verify by comparing the output hash(es) to the input hash(es). This option can be used more than once (see note #3 below for how to generate multiple outputs). Specify the maximum size of each file in the set using ofsz=.

ofsz=BYTES

Set the maximum size of each file in the sets of files specified using ofs= or hofs= to BYTES (see note #5 below). A default value for this option may be set at compile time using -DDEFAULT_OUTPUT_FILE_SIZE followed by the desired value in BYTES.

hash=ALGORITHM

Compute an ALGORITHM hash of the input and also of any outputs specified using hof=, hofs=, or fhod=, where ALGORITHM is one of md5, sha1, sha256, or sha512. This option may be used once for each supported ALGORITHM. Alternatively, hashing can be activated at compile time using one or more of -DDEFAULT_HASH_MD5,-DDEFAULT_HASH_SHA1, -DDEFAULT_HASH_SHA256, and -DDEFAULT_HASH_SHA512.

log=FILE

Log I/O statistcs, diagnostics, and total hashes of input and output to FILE. If hlog= is not specified, piecewise hashes of multiple file input and output are also logged to FILE. This option can be used more than once to generate multiple logs.

hlog=FILE

Log total hashes and piecewise hashes to FILE. This option can be used more than once to generate multiple logs.

mlog=FILE

Create hash log that is easier for machine to read

----------------- advanced options: -----------------

fhod=DEVICE

The same as hof=DEVICE, with additional hashing of the entire output DEVICE. This option can be used more than once (see note #3 below for how to generate multiple outputs).

rec=off

By default, zeros are written to the output(s) in place of bad sectors when the input is a device. Use this option to cause the program to instead exit when a bad sector is encountered.

wipe=DEVICE

Wipe DEVICE by writing zeros (default) or a pattern specified by pat= or tpat=.

hwipe=DEVICE

Wipe DEVICE by writing zeros (default) or a pattern specified by pat= or tpat=. Verify DEVICE after writing it by hashing it and comparing the hash(es) to the input hash(es).

pat=HEX

Use pattern as input, writing HEX to every byte of the output. This option can only be used once and cannot be combined with if=, ifs=, or tpat=.

tpat=TEXT

Use text pattern as input, writing the string TEXT repeatedly to the output. This option can only be used once and cannot be combined with if=, ifs=, or pat=.

cnt=SECTORS

Read only SECTORS input sectors. Must be used with pat= or tpat= if not using the pattern with wipe= or hwipe= to wipe a device.

iskip=SECTORS

Skip SECTORS sectors at start of the input device or file.

oskip=SECTORS

Skip SECTORS sectors at start of the output file. Specifying oskip= automatically sets app=on.

app=on

Do not overwrite an output file specified with of= if it already exists, appending output instead.

ssz=BYTES

Unconditionally use BYTES (see note #5 below) bytes for sector size. If ssz= is not specified, sector size is determined by probing the device; if the probe fails or the target is not a device, a sector size of 512 bytes is assumed.

bufsz=BYTES

Set the size of the internal byte buffers to BYTES (see note #5 below). This effectively sets the maximum number of bytes that may be read at a time from the input. BYTES must be a multiple of sector size. Use this option to fine-tune performance.

verb=on

Activate verbose reporting, where sectors in/out are reported for each file in sets of files specified using ifs=, ofs=, or hofs=. Alternatively, verbose reporting may be activated at compile time using -DDEFAULT_VERBOSE_REPORTING.

nwspc=on

Activate compact reporting, where the use of white space to divide log output into logical sections is suppressed. Alternatively, compact reporting may be activated at compile time using -DDEFAULT_COMPACT_REPORTING.

b10=on

Activate base 10 bytes reporting, where the progress display reports 1000 bytes instead of 1024 bytes as 1 KB. Alternatively, base 10 bytes reporting may be activated at compile time using -DDEFAULT_BASE_TEN_BYTES_REPORTING.

corruptoutput=on

For verification testing and demonstration purposes, corrupt the output file(s) with extra bytes so a hash mismatch is guaranteed.

------------- help options: -------------

--help

display this help and exit

--version

output version information and exit

--flags

display compile-time flags and exit

------ notes: ------

1. To read from stdin, do not specify if=, ifs=, pat=, or tpat=. 2. To write to stdout, do not specify of=, hof=, ofs=, hofs=, fhod=,

wipe=, or hwipe=.

3. To write to multiple outputs specify more than one of of=, hof=, ofs=,

hofs=, or fhod=, in any combination.

4. FMT is a pattern for a sequence of file extensions that can be numerical

starting at zero, numerical starting at one, or alphabetical. Specify FMT by using a series of zeros, ones, or a's, respectively. The number of characters used indicates the desired length of the extensions. For example, a FMT specifier of 0000 indicates four character numerical extensions starting with 0000.

5. BYTES may be followed by the following multiplicative suffixes

c (1), w (2), b (512), kB (1000), K (1024), MB (1000*1000), M (1024*1024), GB (1000*1000*1000), G (1024*1024*1024), and so on for T, P, E, Z, and Y.

6. Consider using cnt=, iskip= and oskip= to work around

unreadable sectors if error recovery fails.

7. Sending an interrupt (e.g., CTRL+C) to dc3dd will cause

the program to report the work completed at the time the interrupt is received and then exit.

dc3dd completed at 2017-04-29 02:23:03 +0000

Author

Written by Paul Rubin, David MacKenzie, Stuart Kemp, Jesse Kornblum, Andrew Medico, Richard Cordovano, and Justin Lowe.

Reporting Bugs

Report bugs to <dc3dd@dc3.mil>.

See Also

The full documentation for dc3dd is maintained as a Texinfo manual.  If the info and dc3dd programs are properly installed at your site, the command

info dc3dd

should give you access to the complete manual.

Referenced By

nwipe(1).

April 2017 dc3dd 7.2.646 User Commands