Re: Slightly OT: non-buffered stdin in Java

Anno domini 2023 Thu, 8 Jun 17:22:38 -0400
 Aryeh Friedman scripsit:
> On Thu, Jun 8, 2023 at 2:39 PM Dr. Nikolaus Klepp <dr.klepp@gmx.at> wrote:
> >
> > Anno domini 2023 Thu, 8 Jun 14:01:19 -0400
> >  Aryeh Friedman scripsit:
> > > Under Java stdin (System.in) is a buffered stream not sent to the
> > > application until return is pressed.  But, Java can read from
> > > files/sockets and other generic InputStreams unbuffered.   So I was
> > > wondering if there is a command that will make stdin go to a file so
> > > that Java can open that file and read it unbuffered?
> > >
> > > I know I can do something like cat ->file but that makes it hard to
> > > sync stdout and stderr (both are unbuffered in Java) with the file
> > > version of stdin
> > >
> >
> > "stdbuf" might be what you look for:
> >
> > https://man.freebsd.org/cgi/man.cgi?query=stdbuf
> 
> Will likely need to play with it more but stdbuf -i 0 -o 0 cat -|cat
> didn't produce the expected immediate echo I still had to hit return
> 

Your console is linebuffered, so "cat" receives lines. IIRC "cat" disables linebuffer on input by itself, so you should use someting else for testing.

Nik

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