MPE/iX Shell and Utilities Reference Manual, Vol 1

dd(1) MPE/iX Shell and Utilities dd(1)
of=file writes output data to file. If you don’t specify this option, dd writes data to the stan-
dard output. dd truncates the output file before writing to it, unless you specified the
seek=n operand. If you specify seek=n, but do not specify conv=notrunc, dd
preserves only those blocks in the output file over which it seeks. If the size of the
seek plus the size of the input file is less than the size of the output file, this can result
in a shortened output file.
omsg=string
displays string when dd runs out of room while writing to the current volume. Any
occurrences of %d in string are replaced with the number of the next volume to be
written. dd then reads and discards a line from the controlling terminal, giving you a
chance to change volumes (usually diskettes).
seek=n
initially seeks to the nth block of the output file.
skip=n
reads and discards the first n blocks of input.
EXAMPLES
dd if=in of=out conv=ascii cbs=80 ibs=6400 obs=512
Converts 80-byte fixed length
EBCDIC punch card images in 6400 byte input blocks to variable
length ASCII lines, 512 bytes to the output block.
DIAGNOSTICS
Possible exit status values are:
0 Successful completion.
1 Failure due to any of the following:
— an option that should contain = does not
— I/O errors on read/write
— invalid command line option
Messages
Message: absolute I/O must be in num byte units
Cause: You attempted to read from, or write to, a device which requires block sizes to
be in multiples of its sector size (in this case, num bytes).
Action: Specify a block size that is a multiple of the device’s sector size.
Commands and Utilities 1-171