1	#!/usr/bin/env bash
2
3	#### case
4	foo=a; case $foo in [0-9]) echo number;; [a-z]) echo letter;; esac
5	## stdout: letter
6
7	#### case in subshell
8	# Hm this subhell has to know about the closing ) and stuff like that.
9	# case_clause is a compound_command, which is a command. And a subshell
10	# takes a compound_list, which is a list of terms, which has and_ors in them
11	# ... which eventually boils down to a command.
12	echo $(foo=a; case $foo in [0-9]) echo number;; [a-z]) echo letter;; esac)
13	## stdout: letter
14
15	#### Command sub word part
16	# "The token shall not be delimited by the end of the substitution."
17	foo=FOO; echo $(echo $foo)bar$(echo $foo)
18	## stdout: FOObarFOO
19
20	#### Backtick
21	foo=FOO; echo `echo $foo`bar`echo $foo`
22	## stdout: FOObarFOO
23
24	#### Backtick 2
25	echo `echo -n l; echo -n s`
26	## stdout: ls
27
28	#### Nested backticks
29	# Inner `` are escaped! Not sure how to do triple.. Seems like an unlikely
30	# use case. Not sure if I even want to support this!
31	echo X > $TMP/000000-first
32	echo `\`echo -n l; echo -n s\` $TMP | grep 000000-first`
33	## stdout: 000000-first
34
35	#### Making command out of command sub should work
36	# Works in bash and dash!
37	$(echo ec)$(echo ho) split builtin
38	## stdout: split builtin
39
40	#### Making keyword out of command sub should NOT work
41	# This doesn't work in bash or dash! Hm builtins are different than keywords /
42	# reserved words I guess.
43	# dash fails, but gives code 0
44	$(echo f)$(echo or) i in a b c; do echo $i; done
45	echo status=$?
46	## stdout-json: ""
47	## status: 2
48	## BUG dash stdout-json: "\nstatus=0\n"
49	## BUG dash status: 0
50	## OK mksh status: 1
51
52	#### Command sub with here doc
53	echo $(<<EOF tac
54	one
55	two
56	EOF
57	)
58	## stdout: two one
59
60	#### Here doc with pipeline
61	<<EOF tac | tr '\n' 'X'
62	one
63	two
64	EOF
65	## stdout-json: "twoXoneX"
66
67	#### Command Sub word split
68	argv.py $(echo 'hi there') "$(echo 'hi there')"
69	## stdout: ['hi', 'there', 'hi there']
70
71	#### Command Sub trailing newline removed
72	s=$(python -c 'print "ab\ncd\n"')
73	argv.py "$s"
74	## stdout: ['ab\ncd']
75
76	#### Command Sub trailing whitespace not removed
77	s=$(python -c 'print "ab\ncd\n "')
78	argv.py "$s"
79	## stdout: ['ab\ncd\n ']
80
81	#### Command Sub and exit code
82	# A command resets the exit code, but an assignment doesn't.
83	echo $(echo x; exit 33)
84	echo $?
85	x=$(echo x; exit 33)
86	echo $?
87	## STDOUT:
88	x
89	0
90	33
91	## END
92
93	#### Command Sub in local sets exit code
94	# A command resets the exit code, but an assignment doesn't.
95	f() {
96	echo $(echo x; exit 33)
97	echo $?
98	local x=$(echo x; exit 33)
99	echo $?
100	}
101	f
102	## STDOUT:
103	x
104	0
105	0
106	## END
107
108	#### Double Quotes in Command Sub in Double Quotes
109	# virtualenv's bin/activate uses this.
110	# This is weird! Double quotes within `` is different than double quotes
111	# within $()! All shells agree.
112	# I think this is related to the nested backticks case!
113	echo "x $(echo hi)"
114	echo "x $(echo "hi")"
115	echo "x $(echo \"hi\")"
116	echo "x `echo hi`"
117	echo "x `echo "hi"`"
118	echo "x `echo \"hi\"`"
119	## STDOUT:
120	x hi
121	x hi
122	x "hi"
123	x hi
124	x hi
125	x hi
126	## END
127
128	#### Escaped quote in [[ ]]
129	file=$TMP/command-sub-dbracket
130	#rm -f $file
131	echo "123 `[[ $(echo \\" > $file) ]]` 456";
132	cat $file
133	## STDOUT:
134	123 456
135	"
136	## END
137
138	#### Quoting $ within ``
139	echo 1 `echo $`
140	echo 2 `echo \$`
141	echo 3 `echo \\$`
142	echo 4 `echo \\\$`
143	echo 5 `echo \\\\$`
144	## STDOUT:
145	1 $
146	2 $
147	3 $
148	4 $
149	5 \$
150	## END
151
152	#### Quoting $ within `` within double quotes
153	echo "1 `echo $`"
154	echo "2 `echo \$`"
155	echo "3 `echo \\$`"
156	echo "4 `echo \\\$`"
157	echo "5 `echo \\\\$`"
158	## STDOUT:
159	1 $
160	2 $
161	3 $
162	4 $
163	5 \$
164	## END
165
166	#### Quoting \ within ``
167	# You need FOUR backslashes to make a literal \.
168	echo [1 `echo \ `]
169	echo [2 `echo \\ `]
170	echo [3 `echo \\\\ `]
171	## STDOUT:
172	[1 ]
173	[2 ]
174	[3 \]
175	## END
176
177	#### Quoting \ within `` within double quotes
178	echo "[1 `echo \ `]"
179	echo "[2 `echo \\ `]"
180	echo "[3 `echo \\\\ `]"
181	## STDOUT:
182	[1 ]
183	[2 ]
184	[3 \]
185	## END
186
187	#### Quoting ( within ``
188	echo 1 `echo \(`
189	echo 2 `echo \\(`
190	echo 3 `echo \\ \\(`
191	## STDOUT:
192	1 (
193	2 (
194	3 (
195	## END
196
197	#### Quoting ( within `` within double quotes
198	echo "1 `echo \(`"
199	echo "2 `echo \\(`"
200	echo "3 `echo \\ \\(`"
201	## STDOUT:
202	1 (
203	2 (
204	3 (
205	## END
206
207	#### Quoting non-special characters within ``
208	echo [1 `echo \z]`
209	echo [2 `echo \\z]`
210	echo [3 `echo \\\z]`
211	echo [4 `echo \\\\z]`
212	## STDOUT:
213	[1 z]
214	[2 z]
215	[3 \z]
216	[4 \z]
217	## END
218
219	#### Quoting non-special characters within `` within double quotes
220	echo "[1 `echo \z`]"
221	echo "[2 `echo \\z`]"
222	echo "[3 `echo \\\z`]"
223	echo "[4 `echo \\\\z`]"
224	## STDOUT:
225	[1 z]
226	[2 z]
227	[3 \z]
228	[4 \z]
229	## END
230
231	#### Quoting double quotes within backticks
232	echo \"foo\" # for comparison
233	echo `echo \"foo\"`
234	echo `echo \\"foo\\"`
235	## STDOUT:
236	"foo"
237	"foo"
238	"foo"
239	## END
240
241	#### More levels of double quotes in backticks
242	# Shells don't agree here, some of them give you form feeds!
243	# There are two levels of processing I don't understand.
244	echo BUG
245	exit
246	echo `echo \\\"foo\\\"`
247	echo `echo \\\\"foo\\\\"`
248	echo `echo \\\\\"foo\\\\\"`
249	## BUG bash/dash/mksh/osh STDOUT:
250	BUG
251	## END
252
253	#### Syntax errors with double quotes within backticks
254
255	# bash does print syntax errors but somehow it exits 0
256
257	$SH -c 'echo `echo "`'
258	echo status=$?
259	$SH -c 'echo `echo \\\\"`'
260	echo status=$?
261
262	## STDOUT:
263	status=2
264	status=2
265	## END
266	## OK mksh STDOUT:
267	status=1
268	status=1
269	## END
270	## OK bash stdout-json: "\nstatus=0\n\nstatus=0\n"