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Copy a file, converting and formatting according to the operands.
| Tag | Description |
|---|---|
| bs=BYTES | |
| force ibs=BYTES and obs=BYTES | |
| cbs=BYTES | |
| convert BYTES bytes at a time | |
| conv=CONVS | |
| convert the file as per the comma separated symbol list | |
| count=BLOCKS | |
| copy only BLOCKS input blocks | |
| ibs=BYTES | |
| read BYTES bytes at a time | |
| if=FILE | |
| read from FILE instead of stdin | |
| iflag=FLAGS | |
| read as per the comma separated symbol list | |
| obs=BYTES | |
| write BYTES bytes at a time | |
| of=FILE | |
| write to FILE instead of stdout | |
| oflag=FLAGS | |
| write as per the comma separated symbol list | |
| seek=BLOCKS | |
| skip BLOCKS obs-sized blocks at start of output | |
| skip=BLOCKS | |
| skip BLOCKS ibs-sized blocks at start of input | |
| status=noxfer | |
| suppress transfer statistics | |
| BLOCKS and BYTES may be followed by the following multiplicative suffixes: xM M, 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, Y. | |
| Each CONV symbol may be: | |
| ascii | from EBCDIC to ASCII |
| ebcdic | from ASCII to EBCDIC |
| ibm | from ASCII to alternate EBCDIC |
| block | pad newline-terminated records with spaces to cbs-size |
| unblock | |
| replace trailing spaces in cbs-size records with newline | |
| lcase | change upper case to lower case |
| nocreat | |
| do not create the output file | |
| excl | fail if the output file already exists |
| notrunc | |
| do not truncate the output file | |
| ucase | change lower case to upper case |
| swab | swap every pair of input bytes |
| noerror | |
| continue after read errors | |
| sync | pad every input block with NULs to ibs-size; when used |
| with block or unblock, pad with spaces rather than NULs | |
| fdatasync physically write output file data before finishing fsync likewise, but also write metadata | |
| Each FLAG symbol may be: | |
| append | append mode (makes sense only for output) |
| direct | use direct I/O for data |
| dsync | use synchronized I/O for data |
| sync | likewise, but also for metadata |
| nonblock | |
| use non-blocking I/O | |
| nofollow | |
| do not follow symlinks | |
| noctty | do not assign controlling terminal from file |
| Sending a USR1 signal to a running ‘dd’ process makes it print I/O statistics to standard error and then resume copying. | |
|
$ dd if=/dev/zero of=/dev/null& pid=$!
$ kill -USR1 $pid; sleep 1; kill $pid | |
| 18335302+0 records in 18335302+0 records out 9387674624 bytes (9.4 GB) copied, 34.6279 seconds, 271 MB/s | |
| Options are: | |
| --help | display this help and exit |
| --version | |
| output version information and exit | |
| Tag | Description |
|---|---|
| info dd |
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