dd.1

操作系统设计与实现源码

.TH DD 1
.SH NAME
dd \- disk dumper
.SH SYNOPSIS
\fBdd\fR [\fIoption = value\fR] ...\fR
.br
.de FL
.TP
\\fB\\$1\\fR
\\$2
..
.de EX
.TP 20
\\fB\\$1\\fR
# \\$2
..
.SH EXAMPLES
.EX "dd if=/dev/fd0 of=/dev/fd1" "Copy disk 0 to disk 1"
.EX "dd if=x of=y bs=1w skip=4" "Copy \fIx\fP to \fIy\fP, skipping 4 words"
.EX "dd if=x of=y count=3" "Copy three 512\-byte blocks"
.SH DESCRIPTION
.PP
This command is intended for copying partial files.
The block size, skip count, and number of blocks to copy can be specified.
The options are:
.PP
.ta 0.25i 1.5i
	\fBif\fR = file	\- Input file (default is \fIstdin\fR)
.br
	\fBof\fR = file	\- Output file (default is standard output)
.br
	\fBibs\fR = n	\- Input block size (default 512 bytes)
.br
	\fBobs\fR = n	\- Output block size (default is 512 bytes)
.br
	\fBbs\fR = n	\- Block size; sets \fIibs\fP and \fIobs\fP (default is 512 bytes)
.br
	\fBskip\fR = n	\- Skip \fIn\fP input blocks before reading
.br
	\fBseek\fR = n	\- Skip \fIn\fP output blocks before writing
.br
	\fBcount\fR = n	\- Copy only \fIn\fP input blocks
.br
	\fBconv = lcase\fR	\- Convert upper case letters to lower case
.br
	\fBconv = ucase\fR	\- Convert lower case letters to upper case
.br
	\fBconv = swab\fR	\- Swap every pair of bytes
.br
	\fBconv = noerror\fR	\- Ignore errors and just keep going
.br
	\fBconv = silent\fR	\- Suppress statistics (Minix specific flag)
.PP
Where sizes are expected, they are in bytes.
However, the letters \fBw\fR, \fBb\fR, or \fBk\fR may be appended to the
number to indicate words (2 bytes), blocks (512 bytes), or K
(1024 bytes), respectively.
When
.I dd
is finished, it reports the number of full and partial blocks read and written.
.SH "SEE ALSO"
.BR vol (1).