dd.1

操作系统设计与实现源码

DD(1)                     Minix Programmer's Manual                      DD(1)


NAME
     dd - disk dumper

SYNOPSIS
     dd [option = value] ...

EXAMPLES

     dd if=/dev/fd0 of=/dev/fd1
                         # Copy disk 0 to disk 1

     dd if=x of=y bs=1w skip=4
                         # Copy x to y, skipping 4 words

     dd if=x of=y count=3
                         # Copy three 512-byte blocks

DESCRIPTION

     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:

        if = file      - Input file (default is stdin)
        of = file      - Output file (default is standard output)
        ibs = n        - Input block size (default 512 bytes)
        obs = n        - Output block size (default is 512 bytes)
        bs = n         - Block size; sets ibs and obs (default is 512 bytes)
        skip = n       - Skip n input blocks before reading
        seek = n       - Skip n output blocks before writing
        count = n      - Copy only n input blocks
        conv = lcase   - Convert upper case letters to lower case
        conv = ucase   - Convert lower case letters to upper case
        conv = swab    - Swap every pair of bytes
        conv = noerror - Ignore errors and just keep going
        conv = silent  - Suppress statistics (Minix specific flag)

     Where sizes are expected, they are in bytes.  However, the letters w,  b,
     or  k  may  be appended to the number to indicate words (2 bytes), blocks
     (512 bytes), or K (1024 bytes), respectively.  When dd  is  finished,  it
     reports the number of full and partial blocks read and written.

SEE ALSO
     vol(1).









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