Re: coproc or whatever in bash and ksh (Was: Different variable assignments)

On 19.10.2024 15:54, Janis Papanagnou wrote:

Lawrence D'Oliveiro  <ldo@nz.invalid> wrote:

>
   coproc { uname -sr; }
   read -u ${COPROC[0]} var3
   wait $COPROC_PID
   echo $var3

>

 
The syntax for the [unnecessary] co-process application depicted
above would in Ksh be
 
  uname -sr |&
  read -p var
  echo "$var"

Concerning the syntax (differences, and generally) I want to add
that it's worthwhile to compare the Ksh syntax with the approach
that we would typically take [in Ksh] to solve the task

  uname -sr | read var
  echo "$var"

We see that the co-process syntax is a straightforward variant of
the ordinary piping. (As opposed to bash that introduces a lot of
[bulky] stuff that's not even resembling in any way the read-pipe.)


For the interested folks let me hijack my post to add that it's
possible to redirect the co-processes to other file descriptors
(using <&p and >&p with appropriate file descriptor numbers) so
that multiple co-processes can be simultaneously used.

Janis