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Does Posix require any devices? For example, /dev/urandom, /dev/zero or /dev/null?

I suspect not because of non-*nix OSes, but wanted to ask for completeness.

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/dev/null /dev/tty ... and ... maybe that's it. It also requires the /tmp path. I know because I once asked a similar question. Oh, and /dev/console. –  mikeserv Jul 26 '14 at 16:34

1 Answer 1

up vote 4 down vote accepted

POSIX general defines three special files:

  • /dev/tty
  • /dev/console
  • /dev/null

In addition, / and /tmp are also defined by POSIX.

/dev/zero, /dev/urandom or /dev/random are defined in some UNIX-like operating systems. Some operating systems may not define them, or implement with different names.


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I've seen nul and console on Windows, but I don't believe I've ever seen tty. –  jww Jul 26 '14 at 16:51
@noloader: Windows implement only the first version of POSIX standard. See: en.wikipedia.org/wiki/Microsoft_POSIX_subsystem –  cuonglm Jul 26 '14 at 16:53
@noloader Windows's nul and console aren't related to Unix's /dev/null and /dev/console except in some indirect historical way. The names nul and console were inherited from CP/M (which didn't have directories); CP/M/DOS/Windows's nul means the same thing as unix's /dev/null but console under DOS and Windows means a serial port, not the console like on unix systems. If you run an application in Windows's POSIX subsystem (or in another POSIX implementation on top of Windows), you will get /dev/null, /dev/tty and /dev/console. –  Gilles Jul 27 '14 at 21:39

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