From: Zach Riggle <zachriggle@gmail.com>
To: zsh-workers@zsh.org
Subject: Where is this =(:) construct documented?
Date: Fri, 11 Jun 2021 14:17:08 -0500 [thread overview]
Message-ID: <CAMP9c5n+K-UYHaEC7fOo0AtL5RFhmWs31aDeiwSGn_BrFan_4A@mail.gmail.com> (raw)
It's insane, cool, and I can't find this documented anywhere. It
creates a temporary file that is automatically deleted... but only
after the line / expression terminates.
( ... ) creates a subshell (terminology?)
( : ) creates a subshell that does nothing
=bash evaluates to the path to bash, e.g. /usr/bin/bash
$(...) captures the output of a subshell, e.g. x=$(echo foo)
If follows, then, that =(:) shows the path to... what? Apparently, a
scope-tracked, auto-deleting temporary file. *Where is this
documented?*
# wat.zsh ####
wat() {
>&2 echo IN WAT
>&2 ls -la "$1"
echo "$1"
}ls -la $(wat =(:))
#############
# example #####
$ zsh wat.sh
IN WAT
-rw------- 1 zachriggle wheel 0 Jun 11 14:13 /tmp/zshfMERth
ls: /tmp/zshfMERth: No such file or directory
#############
What's more insane is that the temporary file will be auto-populated
with the output of the =() construct. Where is THAT documented?
#############
$ (){ echo $1; cat $1 } =( echo allo )
/tmp/zshpfFAOp
allo
#############
Zach Riggle
next reply other threads:[~2021-06-11 19:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 19:17 Zach Riggle [this message]
2021-06-11 19:18 ` Zach Riggle
2021-06-11 19:53 ` Stephane Chazelas
2021-06-11 19:58 ` Roman Perepelitsa
2021-06-11 20:04 ` Stephane Chazelas
2021-06-11 20:39 ` Zach Riggle
2021-06-14 12:44 ` Vincent Lefevre
2021-06-14 14:32 ` Stephane Chazelas
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