cat /dev/urandom

Lane lane at
Wed Jul 27 04:17:51 GMT 2005

On Tuesday 26 July 2005 22:04, you wrote:
> Lane <lane at> 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 

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) 


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