1	#!/bin/bash
2	#
3	# Job control constructs:
4	# & terminator (instead of ;)
5	# $! -- last PID
6	# wait builtin (wait -n waits for next)
7	#
8	# Only interactive:
9	# fg
10	# bg
11	# %1 -- current job
12
13	### wait with nothing to wait for
14	wait
15	# status: 0
16
17	### wait -n with nothing to wait for
18	# The 127 is STILL overloaded. Copying bash for now.
19	wait -n
20	# status: 127
21	# OK dash status: 2
22	# OK mksh status: 1
23
24	### wait with invalid job ID
25	wait %nonexistent
26	# status: 127
27	# OK dash status: 2
28
29	### wait with invalid PID
30	wait %nonexistent
31	# status: 127
32	# OK dash status: 2
33
34	### Builtin in background
35	echo async &
36	wait
37	# stdout: async
38
39	### External command in background
40	sleep 0.01 &
41	wait
42	# stdout-json: ""
43
44	### Pipeline in Background
45	echo hi | exit 99 &
46	wait $!
47	echo status=$?
48	# stdout: status=99
49
50	### Wait sets PIPESTATUS
51	{ echo hi; exit 55; } | exit 99 &
52	echo "pipestatus=${PIPESTATUS[@]}"
53	wait $!
54	echo status=$?
55	echo "pipestatus=${PIPESTATUS[@]}"
56	# stdout-json: "pipestatus=\nstatus=99\npipestatus=55 99\n"
57	# BUG bash stdout-json: "pipestatus=\nstatus=99\npipestatus=0\n"
58	# N-I mksh stdout-json: "pipestatus=0\nstatus=99\npipestatus=0\n"
59	# N-I dash stdout-json: ""
60	# N-I dash status: 2
61
62	### Brace group in background, wait all
63	{ sleep 0.09; exit 9; } &
64	{ sleep 0.07; exit 7; } &
65	wait # wait for all gives 0
66	echo "status=$?"
67	# stdout: status=0
68
69	### Wait on background process PID
70	{ sleep 0.09; exit 9; } &
71	pid1=$!
72	{ sleep 0.07; exit 7; } &
73	pid2=$!
74	wait $pid1
75	echo "status=$?"
76	wait $pid2
77	echo "status=$?"
78	# stdout-json: "status=9\nstatus=7\n"
79
80	### Wait on multiple specific IDs returns last status
81	{ sleep 0.08; exit 8; } &
82	jid1=$!
83	{ sleep 0.09; exit 9; } &
84	jid2=$!
85	{ sleep 0.07; exit 7; } &
86	jid3=$!
87	wait $jid1 $jid2 $jid3 # NOTE: not using %1 %2 %3 syntax on purpose
88	echo "status=$?" # third job I think
89	# stdout: status=7
90
91	### wait -n
92	{ sleep 0.09; exit 9; } &
93	{ sleep 0.07; exit 7; } &
94	wait -n
95	echo "status=$?"
96	wait -n
97	echo "status=$?"
98	# stdout-json: "status=7\nstatus=9\n"
99	# N-I dash stdout-json: "status=2\nstatus=2\n"
100	# N-I mksh stdout-json: "status=1\nstatus=1\n"
101
102	### Async for loop
103	for i in 1 2 3; do
104	echo $i
105	sleep 0.0$i
106	done &
107	wait
108	# stdout-json: "1\n2\n3\n"
109	# status: 0
110
111	### Background process doesn't affect parent
112	echo ${foo=1}
113	echo $foo
114	echo ${bar=2} &
115	wait
116	echo $bar # bar is NOT SET in the parent process
117	# stdout-json: "1\n1\n2\n\n"