1	#!/usr/bin/env 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 jobspec syntax %nonexistent
25	wait %nonexistent
26	## status: 127
27	## OK dash status: 2
28
29	#### wait with invalid PID
30	wait 12345678
31	## status: 127
32
33	#### wait with invalid arg
34	wait zzz
35	## status: 2
36	## OK bash status: 1
37	# mksh confuses a syntax error with 'command not found'!
38	## BUG mksh status: 127
39
40	#### Builtin in background
41	echo async &
42	wait
43	## stdout: async
44
45	#### External command in background
46	sleep 0.01 &
47	wait
48	## stdout-json: ""
49
50	#### Pipeline in Background
51	echo hi | { exit 99; } &
52	wait $!
53	echo status=$?
54	## stdout: status=99
55
56	#### Wait sets PIPESTATUS
57	{ echo hi; exit 55; } | { exit 99; } &
58	echo "pipestatus=${PIPESTATUS[@]}"
59	wait $!
60	echo status=$?
61	echo "pipestatus=${PIPESTATUS[@]}"
62	## stdout-json: "pipestatus=\nstatus=99\npipestatus=55 99\n"
63	## BUG bash stdout-json: "pipestatus=\nstatus=99\npipestatus=0\n"
64	## N-I mksh stdout-json: "pipestatus=0\nstatus=99\npipestatus=0\n"
65	## N-I dash stdout-json: ""
66	## N-I dash status: 2
67
68	#### Brace group in background, wait all
69	{ sleep 0.09; exit 9; } &
70	{ sleep 0.07; exit 7; } &
71	wait # wait for all gives 0
72	echo "status=$?"
73	## stdout: status=0
74
75	#### Wait on background process PID
76	{ sleep 0.09; exit 9; } &
77	pid1=$!
78	{ sleep 0.07; exit 7; } &
79	pid2=$!
80	wait $pid1
81	echo "status=$?"
82	wait $pid2
83	echo "status=$?"
84	## stdout-json: "status=9\nstatus=7\n"
85
86	#### Wait on multiple specific IDs returns last status
87	{ sleep 0.08; exit 8; } &
88	jid1=$!
89	{ sleep 0.09; exit 9; } &
90	jid2=$!
91	{ sleep 0.07; exit 7; } &
92	jid3=$!
93	wait $jid1 $jid2 $jid3 # NOTE: not using %1 %2 %3 syntax on purpose
94	echo "status=$?" # third job I think
95	## stdout: status=7
96
97	#### wait -n
98	{ sleep 0.09; exit 9; } &
99	{ sleep 0.03; exit 3; } &
100	wait -n
101	echo "status=$?"
102	wait -n
103	echo "status=$?"
104	## stdout-json: "status=3\nstatus=9\n"
105	## N-I dash stdout-json: "status=2\nstatus=2\n"
106	## N-I mksh stdout-json: "status=1\nstatus=1\n"
107
108	#### Async for loop
109	for i in 1 2 3; do
110	echo $i
111	sleep 0.0$i
112	done &
113	wait
114	## stdout-json: "1\n2\n3\n"
115	## status: 0
116
117	#### Background process doesn't affect parent
118	echo ${foo=1}
119	echo $foo
120	echo ${bar=2} &
121	wait
122	echo $bar # bar is NOT SET in the parent process
123	## stdout-json: "1\n1\n2\n\n"