z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

dd
Example
ibs=size
Sets the input block size in bytes. You specify it in the same way as with
the bs option.
if=file Reads input data from file. If you don’t specify this option, dd reads data
from standard input (stdin).
imsg=string
Displays string when all data has been read from the current volume,
replacing all occurrences of %d in string with the number of the next volume
to be read. dd then reads and discards a line from the controlling terminal.
iseek=n
seeks to the nth block of the input file. The distinction between this and the
skip option is that iseek does not read the discarded data. There are some
devices, however, such as tape drives and communication lines, on which
seeking is not possible, so only skip is appropriate.
obs=size
Sets the output block size in bytes. You specify it in the same way as the
bs value. The size of the destination should be a multiple of the value
chosen for size. For example, if you choose obs=10K, the destination’s size
should be a multiple of 10K.
of=file Writes output data to file. If you don’t specify this option, dd writes data to
standard output (stdout). 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.
seek=n
Initially seeks to the nth block of the output file.
skip=n
Entering:
Note: Use caution when working with DBCS characters and the seek
option. Seeking into the output file that contains DBCS characters
can cause the DBCS string in the output file to be corrupted. Be sure
that the seek count is not aligned with an existing DBCS string in the
output file. Otherwise, part of the existing DBCS string either is
written over with singlebyte data or has extra shift codes from the
input file’s DBCS data.
Reads and discards the first n blocks of input.
dd if=in of=out conv=ascii cbs=80 ibs=6400 obs=512
converts 80-byte fixed-length EBCDIC card images in 6400-byte input blocks to
variable-length ASCII lines, 512 bytes to the output block.
232 z/OS V1R9.0 UNIX System Services Command Reference