Re: Examples of concurrent coproc usage?

[Carl Edquist]

On Wed, 17 Apr 2024, Chet Ramey wrote:

> On 4/16/24 2:46 AM, Carl Edquist wrote:
>
> > But the shell is pretty slow when you ask it to shovel data around like 
> > this.  The 'read' builtin, for instance, cautiously does read(2) calls 
> > of a single byte at a time.
>
> It has to do it that way to find the delimiter on a non-seekable file 
> descriptor, since it has to leave everything it didn't consume available 
> on stdin.

Understood, and I wouldn't have it any other way.  It's entirely 
appropriate for reading relatively small amounts of data into shell 
variables.  I'm just saying for copying or filtering a substantial amount 
of data, it's 1000x better to use a suitable external command instead.

It makes me cringe a bit and sigh when I see people put something like

        while read X; do echo "$X"; done

in a script, because they somehow imagine it to be more efficient than 
simply running "cat" .

Carl