2 ms·

> everything is text Everything is a byte stream. Usually that means text but sometimes it doesn't. Which means you can do fun stuff like: - copy file systems

> everything is text Everything is a byte stream. Usually that means text but sometimes it doesn't. Which means you can do fun stuff like: - copy file systems over a network: https://docs.oracle.com/cd/E18752_01/html/819-5461/gbchx.html https://docs.oracle.com/cd/E18752_01/html/819-5461/gbchx.htm... - stream a file into gzip - backup or restore an SD card using `cat`

jrumbut 6y ago
Also dd, which may be the disk destroyer but is also a great tool for binary file miracles. See one here: https://unix.stackexchange.com/questions/6852/best-way-to-remove-bytes-from-the-start-of-a-file https://unix.stackexchange.com/questions/6852/best-way-to-re...
- dredmorbius 6y ago
  "data definition", from MVS JCL. https://news.ycombinator.com/user?id=dredmorbius https://news.ycombinator.com/user?id=dredmorbius
  - mjevans 6y ago
    I recall hearing conjecture that cc was already a routine, and that "copy and convert" became dd as a result in a really old system that may have been pre-unix. Researching, it appears that there are multiple attributions, because it's just that obvious and necessary a routine. https://www2.cs.duke.edu/csl/docs/unix_course/intro-98.html https://www2.cs.duke.edu/csl/docs/unix_course/intro-98.html https://unix.stackexchange.com/questions/6804/what-does-dd-stand-for https://unix.stackexchange.com/questions/6804/what-does-dd-s... https://en.wikipedia.org/wiki/Dd_(Unix) https://en.wikipedia.org/wiki/Dd_(Unix)
  - jrumbut 6y ago
    Yeah disk destroyer or data deleter or whatever is the old joke, not it's actual name. For those unaware, dd has often been used for stuff like overwriting a file with random noise as a homespun secure delete function, and it can do a lot of damage with small typos in the command. Could have used a \s or something to clarify.
- laumars 6y ago
  dd doesn’t example byte stream pipelines though ;) But yes, that’s the typical file / block management tool. Just remember to set a block size otherwise you’d suffer from worse performance than using cat
  - jrumbut 6y ago
    You're right! I was planning to tell a story about some bulk file changes using dd, but then I saw it was a giant "you had to be there" story so I posted with half a context.

jrumbut 6y ago

Also dd, which may be the disk destroyer but is also a great tool for binary file miracles. See one here: https://unix.stackexchange.com/questions/6852/best-way-to-remove-bytes-from-the-start-of-a-file https://unix.stackexchange.com/questions/6852/best-way-to-re...

dredmorbius 6y ago
"data definition", from MVS JCL. https://news.ycombinator.com/user?id=dredmorbius https://news.ycombinator.com/user?id=dredmorbius
- mjevans 6y ago
  I recall hearing conjecture that cc was already a routine, and that "copy and convert" became dd as a result in a really old system that may have been pre-unix. Researching, it appears that there are multiple attributions, because it's just that obvious and necessary a routine. https://www2.cs.duke.edu/csl/docs/unix_course/intro-98.html https://www2.cs.duke.edu/csl/docs/unix_course/intro-98.html https://unix.stackexchange.com/questions/6804/what-does-dd-stand-for https://unix.stackexchange.com/questions/6804/what-does-dd-s... https://en.wikipedia.org/wiki/Dd_(Unix) https://en.wikipedia.org/wiki/Dd_(Unix)
- jrumbut 6y ago
  Yeah disk destroyer or data deleter or whatever is the old joke, not it's actual name. For those unaware, dd has often been used for stuff like overwriting a file with random noise as a homespun secure delete function, and it can do a lot of damage with small typos in the command. Could have used a \s or something to clarify.
laumars 6y ago
dd doesn’t example byte stream pipelines though ;) But yes, that’s the typical file / block management tool. Just remember to set a block size otherwise you’d suffer from worse performance than using cat
- jrumbut 6y ago
  You're right! I was planning to tell a story about some bulk file changes using dd, but then I saw it was a giant "you had to be there" story so I posted with half a context.