Date: Tue, 26 Jul 2005 22:56:38 -0500 From: Lane <lane@joeandlane.com> To: freebsd-questions@freebsd.org Subject: Re: cat /dev/urandom Message-ID: <200507262256.39161.lane@joeandlane.com> In-Reply-To: <p5d5p5ymnq.5p5@mail.opusnet.com> References: <20050726183029.M97284@neptune.atopia.net> <200507262019.25060.lane@joeandlane.com> <p5d5p5ymnq.5p5@mail.opusnet.com>
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On Tuesday 26 July 2005 22:04, you wrote: > Lane <lane@joeandlane.com> writes: > > I think the backticks (and shell variables) actually send the output to a > > pipe, not the screen. > > I don't know why you said either part of that. I didn't imply the > latter and AFAIK the former is untrue (unless you ask the shell to > send their output to a pipe); they "send" their command output > (or variable value) to the shell as it does command and variable > subsitution on your shell command line. Read "Command Substitution" > in the "sh" manpage. I suppose there might be pipes involved in the > shell innerds, but it's not useful to think about them. The output of > the backticks, etc., becomes a part of the post-subsitution command > input to the shell. The shell might or might not then send some of it > to the screen, or run a command that outputs to the screen, depending > upon what the command is. Hmmm ... yeah, that seems right. Sorry I mentioned "pipe" ... I guess I was thinking mostly about how someone had said the output was sent to the screen ... and after I picked myself off the floor from that one I just typed in haste. Not that the output never goes to the screen, of course. It just seemed like the guy was speaking all in terms of screens, and I knew that my experience had that output usually going somewhere other than the screen ... mostly to a pipe. Just typed too soon, and didn't proof, I guess. I hope no harm has been done. For anyone listening .... don't type `cat /dev/urandom` because the results are, as they say, "undefined," and potentially (although probably remotely) destructive. lane
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