1 |
#!/usr/bin/env bash |
2 |
# |
3 |
# Interesting interpretation of constants. |
4 |
# |
5 |
# "Constants with a leading 0 are interpreted as octal numbers. A leading ‘0x’ |
6 |
# or ‘0X’ denotes hexadecimal. Otherwise, numbers take the form [base#]n, where |
7 |
# the optional base is a decimal number between 2 and 64 representing the |
8 |
# arithmetic base, and n is a number in that base. If base# is omitted, then |
9 |
# base 10 is used. When specifying n, the digits greater than 9 are represented |
10 |
# by the lowercase letters, the uppercase letters, ‘@’, and ‘_’, in that order. |
11 |
# If base is less than or equal to 36, lowercase and uppercase letters may be |
12 |
# used interchangeably to represent numbers between 10 and 35. " |
13 |
# |
14 |
# NOTE $(( 8#9 )) can fail, and this can be done at parse time... |
15 |
|
16 |
### Side Effect in Array Indexing |
17 |
a=(4 5 6) |
18 |
echo "${a[b=2]} b=$b" |
19 |
# stdout: 6 b=2 |
20 |
# OK zsh stdout: 5 b=2 |
21 |
# N-I dash stdout-json: "" |
22 |
# N-I dash status: 2 |
23 |
|
24 |
### Add one to var |
25 |
i=1 |
26 |
echo $(($i+1)) |
27 |
# stdout: 2 |
28 |
|
29 |
### $ is optional |
30 |
i=1 |
31 |
echo $((i+1)) |
32 |
# stdout: 2 |
33 |
|
34 |
### SimpleVarSub within arith |
35 |
echo $(($j + 1)) |
36 |
# stdout: 1 |
37 |
|
38 |
### BracedVarSub within ArithSub |
39 |
echo $((${j:-5} + 1)) |
40 |
# stdout: 6 |
41 |
|
42 |
### Arith word part |
43 |
foo=1; echo $((foo+1))bar$(($foo+1)) |
44 |
# stdout: 2bar2 |
45 |
|
46 |
### Arith sub with word parts |
47 |
# Making 13 from two different kinds of sub. Geez. |
48 |
echo $((1 + $(echo 1)${undefined:-3})) |
49 |
# stdout: 14 |
50 |
|
51 |
### Constant with quotes like '1' |
52 |
# NOTE: Compare with [[. That is a COMMAND level expression, while this is a |
53 |
# WORD level expression. |
54 |
echo $(('1' + 2)) |
55 |
# status: 0 |
56 |
# N-I bash/zsh status: 1 |
57 |
# N-I dash status: 2 |
58 |
|
59 |
### Arith sub within arith sub |
60 |
# This is unnecessary but works in all shells. |
61 |
echo $((1 + $((2 + 3)) + 4)) |
62 |
# stdout: 10 |
63 |
|
64 |
### Backticks within arith sub |
65 |
# This is unnecessary but works in all shells. |
66 |
echo $((`echo 1` + 2)) |
67 |
# stdout: 3 |
68 |
|
69 |
### Invalid string to int |
70 |
# bash, mksh, and zsh all treat strings that don't look like numbers as zero. |
71 |
s=foo |
72 |
echo $((s+5)) |
73 |
# OK dash stdout-json: "" |
74 |
# OK dash status: 2 |
75 |
# OK bash/mksh/zsh/osh stdout: 5 |
76 |
# OK bash/mksh/zsh/osh status: 0 |
77 |
|
78 |
### Invalid string to int with strict-arith |
79 |
set -o strict-arith || true |
80 |
s=foo |
81 |
echo $s |
82 |
echo $((s+5)) |
83 |
# status: 1 |
84 |
# stdout-json: "foo\n" |
85 |
# N-I bash status: 0 |
86 |
# N-I bash stdout-json: "foo\n5\n" |
87 |
# N-I dash status: 2 |
88 |
# N-I dash stdout-json: "" |
89 |
# N-I mksh status: 1 |
90 |
# N-I mksh stdout-json: "" |
91 |
# N-I zsh status: 1 |
92 |
# N-I zsh stdout-json: "" |
93 |
|
94 |
### Newline in the middle of expression |
95 |
echo $((1 |
96 |
+ 2)) |
97 |
# stdout: 3 |
98 |
|
99 |
### Ternary operator |
100 |
a=1 |
101 |
b=2 |
102 |
echo $((a>b?5:10)) |
103 |
# stdout: 10 |
104 |
|
105 |
### Preincrement |
106 |
a=4 |
107 |
echo $((++a)) |
108 |
echo $a |
109 |
# stdout-json: "5\n5\n" |
110 |
# N-I dash status: 0 |
111 |
# N-I dash stdout-json: "4\n4\n" |
112 |
|
113 |
### Postincrement |
114 |
a=4 |
115 |
echo $((a++)) |
116 |
echo $a |
117 |
# stdout-json: "4\n5\n" |
118 |
# N-I dash status: 2 |
119 |
# N-I dash stdout-json: "" |
120 |
|
121 |
### Increment undefined variables |
122 |
(( undef1++ )) |
123 |
(( ++undef2 )) |
124 |
echo "[$undef1][$undef2]" |
125 |
# stdout: [1][1] |
126 |
# N-I dash stdout-json: "[][]\n" |
127 |
|
128 |
### Increment and decrement array |
129 |
a=(5 6 7 8) |
130 |
(( a[0]++, ++a[1], a[2]--, --a[3] )) |
131 |
(( undef[0]++, ++undef[1], undef[2]--, --undef[3] )) |
132 |
echo "${a[@]}" - "${undef[@]}" |
133 |
# stdout: 6 7 6 7 - 1 1 -1 -1 |
134 |
# N-I dash stdout-json: "" |
135 |
# N-I dash status: 2 |
136 |
# BUG zsh stdout: 5 6 7 8 - |
137 |
|
138 |
### Increment undefined variables with nounset |
139 |
set -o nounset |
140 |
(( undef1++ )) |
141 |
(( ++undef2 )) |
142 |
echo "[$undef1][$undef2]" |
143 |
# stdout-json: "" |
144 |
# status: 1 |
145 |
# OK dash status: 2 |
146 |
# BUG mksh/zsh status: 0 |
147 |
# BUG mksh/zsh stdout-json: "[1][1]\n" |
148 |
|
149 |
### Comma operator (borrowed from C) |
150 |
a=1 |
151 |
b=2 |
152 |
echo $((a,(b+1))) |
153 |
# stdout: 3 |
154 |
# N-I dash status: 2 |
155 |
# N-I dash stdout-json: "" |
156 |
|
157 |
### Augmented assignment |
158 |
a=4 |
159 |
echo $((a+=1)) |
160 |
echo $a |
161 |
# stdout-json: "5\n5\n" |
162 |
|
163 |
### Comparison Ops |
164 |
echo $(( 1 == 1 )) |
165 |
echo $(( 1 != 1 )) |
166 |
echo $(( 1 < 1 )) |
167 |
echo $(( 1 <= 1 )) |
168 |
echo $(( 1 > 1 )) |
169 |
echo $(( 1 >= 1 )) |
170 |
# stdout-json: "1\n0\n0\n1\n0\n1\n" |
171 |
|
172 |
### Logical Ops |
173 |
echo $((1 || 2)) |
174 |
echo $((1 && 2)) |
175 |
echo $((!(1 || 2))) |
176 |
# stdout-json: "1\n1\n0\n" |
177 |
|
178 |
### Logical Ops Short Circuit |
179 |
x=11 |
180 |
(( 1 || (x = 22) )) |
181 |
echo $x |
182 |
(( 0 || (x = 33) )) |
183 |
echo $x |
184 |
(( 0 && (x = 44) )) |
185 |
echo $x |
186 |
(( 1 && (x = 55) )) |
187 |
echo $x |
188 |
# stdout-json: "11\n33\n33\n55\n" |
189 |
# N-I dash stdout-json: "11\n11\n11\n11\n" |
190 |
|
191 |
### Bitwise ops |
192 |
echo $((1|2)) |
193 |
echo $((1&2)) |
194 |
echo $((1^2)) |
195 |
echo $((~(1|2))) |
196 |
# stdout-json: "3\n0\n3\n-4\n" |
197 |
|
198 |
### Unary minus and plus |
199 |
a=1 |
200 |
b=3 |
201 |
echo $((- a + + b)) |
202 |
# stdout-json: "2\n" |
203 |
|
204 |
### No floating point |
205 |
echo $((1 + 2.3)) |
206 |
# status: 2 |
207 |
# OK bash/mksh status: 1 |
208 |
# BUG zsh status: 0 |
209 |
|
210 |
### Array indexing in arith |
211 |
# zsh does 1-based indexing! |
212 |
array=(1 2 3 4) |
213 |
echo $((array[1] + array[2]*3)) |
214 |
# stdout: 11 |
215 |
# OK zsh stdout: 7 |
216 |
# N-I dash status: 2 |
217 |
# N-I dash stdout-json: "" |
218 |
|
219 |
### Constants in base 36 |
220 |
echo $((36#a))-$((36#z)) |
221 |
# stdout: 10-35 |
222 |
# N-I dash stdout-json: "" |
223 |
# N-I dash status: 2 |
224 |
|
225 |
### Constants in bases 2 to 64 |
226 |
# This is a truly bizarre syntax. Oh it comes from zsh... which allows 36. |
227 |
echo $((64#a))-$((64#z)), $((64#A))-$((64#Z)), $((64#@)), $(( 64#_ )) |
228 |
# stdout: 10-35, 36-61, 62, 63 |
229 |
# N-I dash stdout-json: "" |
230 |
# N-I dash status: 2 |
231 |
# N-I mksh/zsh stdout-json: "" |
232 |
# N-I mksh/zsh status: 1 |
233 |
|
234 |
### Dynamic base constants |
235 |
base=16 |
236 |
echo $(( ${base}#a )) |
237 |
# stdout: 10 |
238 |
# N-I dash stdout-json: "" |
239 |
# N-I dash status: 2 |
240 |
|
241 |
### Octal constant |
242 |
echo $(( 011 )) |
243 |
# stdout: 9 |
244 |
# N-I mksh/zsh stdout: 11 |
245 |
|
246 |
### Dynamic octal constant |
247 |
zero=0 |
248 |
echo $(( ${zero}11 )) |
249 |
# stdout: 9 |
250 |
# N-I mksh/zsh stdout: 11 |
251 |
|
252 |
### Dynamic hex constants |
253 |
zero=0 |
254 |
echo $(( ${zero}xAB )) |
255 |
# stdout: 171 |
256 |
|
257 |
### Dynamic var names - result of runtime parse/eval |
258 |
foo=5 |
259 |
x=oo |
260 |
echo $(( foo + f$x + 1 )) |
261 |
# stdout: 11 |
262 |
|
263 |
### Bizarre recursive name evaluation - result of runtime parse/eval |
264 |
foo=5 |
265 |
bar=foo |
266 |
spam=bar |
267 |
eggs=spam |
268 |
echo $((foo+1)) $((bar+1)) $((spam+1)) $((eggs+1)) |
269 |
# stdout: 6 6 6 6 |
270 |
# N-I dash stdout-json: "" |
271 |
# N-I dash status: 2 |
272 |
|
273 |
### nounset with arithmetic |
274 |
set -o nounset |
275 |
x=$(( y + 5 )) |
276 |
echo "should not get here: x=${x:-<unset>}" |
277 |
# stdout-json: "" |
278 |
# status: 1 |
279 |
# BUG dash/mksh/zsh stdout: should not get here: x=5 |
280 |
# BUG dash/mksh/zsh status: 0 |
281 |
|
282 |
### Integer Overflow |
283 |
set -o nounset |
284 |
echo $(( 999999 * 999999 * 999999 * 999999 )) |
285 |
# stdout: 999996000005999996000001 |
286 |
# BUG dash/bash/zsh stdout: -1996229794797103359 |
287 |
# BUG mksh stdout: -15640831 |
288 |
|
289 |
### Invalid LValue |
290 |
a=9 |
291 |
(( (a + 2) = 3 )) |
292 |
echo $a |
293 |
# status: 2 |
294 |
# stdout-json: "" |
295 |
# OK bash/mksh/zsh stdout: 9 |
296 |
# OK bash/mksh/zsh status: 0 |
297 |
# dash doesn't implement assignment |
298 |
# N-I dash status: 2 |
299 |
# N-I dash stdout-json: "" |
300 |
|
301 |
### Invalid LValue that looks like array |
302 |
(( 1[2] = 3 )) |
303 |
echo "status=$?" |
304 |
# status: 2 |
305 |
# stdout-json: "" |
306 |
# OK bash stdout: status=1 |
307 |
# OK bash status: 0 |
308 |
# OK mksh/zsh stdout: status=2 |
309 |
# OK mksh/zsh status: 0 |
310 |
# N-I dash stdout: status=127 |
311 |
# N-I dash status: 0 |
312 |
|
313 |
### Invalid LValue: two sets of brackets |
314 |
(( a[1][2] = 3 )) |
315 |
echo "status=$?" |
316 |
# shells treat this as a NON-fatal error |
317 |
# status: 2 |
318 |
# stdout-json: "" |
319 |
# OK bash stdout: status=1 |
320 |
# OK mksh/zsh stdout: status=2 |
321 |
# OK bash/mksh/zsh status: 0 |
322 |
# dash doesn't implement assignment |
323 |
# N-I dash stdout: status=127 |
324 |
# N-I dash status: 0 |
325 |
|