1	#!/bin/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"