1	#!/usr/bin/env bash
2
3	### Process sub input
4	f=_tmp/process-sub.txt
5	{ echo 1; echo 2; echo 3; } > $f
6	comm <(head -n 2 $f) <(tail -n 2 $f)
7	# stdout-json: "1\n\t\t2\n\t3\n"
8
9	### Non-linear pipeline with >()
10	stdout_stderr() {
11	echo o1
12	echo o2
13
14	sleep 0.1 # Does not change order
15
16	{ echo e1;
17	echo warning: e2
18	echo e3;
19	} >& 2
20	}
21	stdout_stderr 2> >(grep warning) | tac >out.txt
22	wait $! # this does nothing in bash 4.3, but probably does in bash 4.4.
23	echo OUT
24	cat out.txt
25	# PROBLEM -- OUT comes first, and then 'warning: e2', and then 'o2 o1'. It
26	# looks like it's because nobody waits for the proc sub.
27	# http://lists.gnu.org/archive/html/help-bash/2017-06/msg00018.html
28	# stdout-json: "OUT\nwarning: e2\no2\no1\n"