1	#!/bin/bash
2
3	### $PWD
4	# Just test that it has a slash for now.
5	echo $PWD | grep -o /
6	# status: 0
7
8	### $?
9	echo $? # starts out as 0
10	sh -c 'exit 33'
11	echo $?
12	# stdout-json: "0\n33\n"
13	# status: 0
14
15	### $#
16	set -- 1 2 3 4
17	echo $#
18	# stdout: 4
19	# status: 0
20
21	### $-
22	# dash's behavior seems most sensible here?
23	$SH -o nounset -c 'echo $-'
24	# OK bash stdout: huBc
25	# OK dash stdout: u
26	# OK mksh stdout: uhc
27	# status: 0
28
29	### $_
30	# This is bash-specific.
31	echo hi
32	echo $_
33	# stdout-json: "hi\nhi\n"
34	# N-I dash/mksh stdout-json: "hi\n\n"
35
36	### PID $$
37	# Just test that it has decimal digits
38	echo $$ | egrep '[0-9]+'
39	# status: 0
40
41	### Background PID $!
42	# Just test that it has decimal digits
43	sleep 0.01 &
44	echo $! | egrep '[0-9]+'
45	wait
46	# status: 0
47
48	### $PPID
49	expr $0 : '.*/osh$' && exit 99 # Disabled because of spec-runner.sh issue
50	echo $PPID | egrep '[0-9]+'
51	# Disabled because of spec-runner.sh issue: bash sets it for osh
52	# status: 0
53
54	# NOTE: There is also $BASHPID
55
56	### $PIPESTATUS
57	echo hi | sh -c 'cat; exit 33' | wc -l >/dev/null
58	argv.py "${PIPESTATUS[@]}"
59	# status: 0
60	# stdout: ['0', '33', '0']
61	# N-I dash stdout-json: ""
62	# N-I dash status: 2
63
64	### $RANDOM
65	expr $0 : '.*/osh$' && exit 99 # Disabled because of spec-runner.sh issue
66	echo $RANDOM | egrep '[0-9]+'
67	# status: 0
68	# N-I dash status: 1