Re: Where is this =(:) construct documented?

[Stephane Chazelas <stephane@xxxxxxxxxxxx>]

2021-06-11 20:53:22 +0100, Stephane Chazelas:
[...]
> info zsh "Process Substitution"
[...]

For information, searching in info (with / or s or Ctrl+S) these
days uses extended regexps. So, to search for =(, you need to
search for =\( or toggle regexp matching off first with R. See
info info / for details.

[...]
> That's the third form of process substitution.
> 
> ksh introduced the first two <(...) and >(...) in the 80s. zsh
> added that third form in the 90s.

Already in ksh86. In ksh86 you could actually also use A (B) in
place of A <(B) though it looks like it was removed in later
versions. rc also had process substitution with a different
syntax IIRC.

See also:

https://unix.stackexchange.com/questions/49918/when-was-process-substitution-first-introduced/49952#49952

and

https://unix.stackexchange.com/questions/181937/how-create-a-temporary-file-in-shell-script/181996#181996

-- 
Stephane