DD(1)

📦
version 9.10 · 5 versions
, in ubuntu stonking

💾 NAME 💾

okay bestie, meet dd — the manual page we're reading is dd(1) — and what it does is convert and copy a file. that's it. that's the whole vibe. she's giving "I can do literally anything if you speak to me in operands" and honestly? iconic. 👑

✨ SYNOPSIS ✨

dd [OPERAND]...
dd OPTION

🦋 DESCRIPTION 🦋

so basically: she copies a file, and she converts + formats it based on the operands you hand her. no cap, that's the whole thing. let's go through every single operand because we are NOT skipping any 💅

  • bs=BYTES — read and write up to BYTES bytes at a time (default: 512). she's highkey overrides ibs and obs when she shows up, so know that.
  • cbs=BYTES — convert BYTES bytes at a time.
  • conv=CONVS — convert the file as per the comma separated symbol list (check the big list below, it's giving variety 🌈).
  • count=N — copy only N input blocks. just N. not N+1. N.
  • ibs=BYTES — read up to BYTES bytes at a time (default: 512).
  • if=FILE — read from FILE instead of standard input.
  • iflag=FLAGS — read as per the comma separated symbol list.
  • obs=BYTES — write BYTES bytes at a time (default: 512).
  • of=FILE — write to FILE instead of standard output.
  • oflag=FLAGS — write as per the comma separated symbol list.
  • seek=N (or oseek=N) — skip N obs sized output blocks.
  • skip=N (or iseek=N) — skip N ibs sized input blocks.
  • status=LEVEL — the LEVEL of information to print to standard error; 'none' suppresses everything but error messages, 'noxfer' suppresses the final transfer statistics, 'progress' shows periodic transfer statistics. pick your girlie, choose your gossip level 🗣️

🔢 the suffix lore (N and BYTES edition) 🔢

N and BYTES may be followed by the following multiplicative suffixes, and yes bestie you need all of them:

c=1, w=2, b=512, kB=1000, K=1024, MB=1000*1000, M=1024*1024, xM=M, GB=1000*1000*1000, G=1024*1024*1024, and so on for T, P, E, Z, Y, R, Q.

Binary prefixes can be used, too: KiB=K, MiB=M, and so on.

heads up bestie: if N ends in 'B', it counts bytes not blocks. lowkey the most important plot twist here.

💖 the CONV symbols, one by one 💖

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.
  • ucase — change lower case to upper case.
  • sparse — try to seek rather than write all-NUL output blocks.
  • swab — swap every pair of input bytes. little byte shuffle, slay. 🔄
  • sync — pad every input block with NULs to ibs-size; when used with block or unblock, pad with spaces rather than NULs.
  • excl — fail if the output file already exists.
  • nocreat — do not create the output file.
  • notrunc — do not truncate the output file.
  • noerror — continue after read errors. she's resilient, she's main character energy.
  • fdatasync — physically write output file data before finishing.
  • fsync — likewise, but also write metadata.

🌸 the FLAG symbols, one by one 🌸

each FLAG symbol may be:

  • append — append mode (makes sense only for output; conv=notrunc suggested).
  • direct — use direct I/O for data.
  • directory — fail unless a directory.
  • dsync — use synchronized I/O for data.
  • sync — likewise, but also for metadata.
  • fullblock — accumulate full blocks of input (iflag only).
  • nonblock — use non-blocking I/O.
  • noatime — do not update access time.
  • nocache — Request to drop cache. See also oflag=sync.
  • noctty — do not assign controlling terminal from file.
  • nofollow — do not follow symlinks.

📢 the USR1 situation 📢

sending a USR1 signal to a running 'dd' process makes it print I/O statistics to standard error and then resume copying. so like, if you wanna peek at how she's doing mid-run, just USR1 her, she'll spill the stats and get right back to work. obsessed. 💅

⭐ Options ⭐

options are:

  • --help — display this help and exit.
  • --version — output version information and exit.

👑 AUTHOR 👑

Written by Paul Rubin, David MacKenzie, and Stuart Kemp. three absolute legends, fr fr. 🫶

🐛 REPORTING BUGS 🐛

🌈 SEE ALSO 🌈

Packaged by Ubuntu (9.10-1ubuntu2) Copyright © 2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

ok that's the whole page, you ate that bestie 💖 go copy some files responsibly, and remember: GNU coreutils 9.10, dated August 2026 — that's the version energy this page was born from. mwah 🎀✨
📦 where this page comes from