1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371
|
.\"t
.\" Automatically generated by Pandoc 1.19.2.1
.\"
.TH "JO" "1" "" "User Manuals" ""
.hy
.SH NAME
.PP
jo \- JSON output from a shell
.SH SYNOPSIS
.PP
jo [\-p] [\-a] [\-B] [\-v] [\-V] [\-\-] [ [\-s|\-n|\-b] word ...]
.SH DESCRIPTION
.PP
\f[I]jo\f[] creates a JSON string on \f[I]stdout\f[] from _word_s given
it as arguments or read from \f[I]stdin\f[].
Without option \f[C]\-a\f[] it generates an object whereby each
\f[I]word\f[] is a \f[C]key=value\f[] (or \f[C]key\@value\f[]) pair with
\f[I]key\f[] being the JSON object element and \f[I]value\f[] its value.
\f[I]jo\f[] attempts to guess the type of \f[I]value\f[] in order to
create number (using \f[I]strtod(3)\f[]), string, or null values in
JSON.
.PP
\f[I]jo\f[] treats \f[C]key\@value\f[] specifically as boolean JSON
elements: if the value begins with \f[C]T\f[], \f[C]t\f[], or the
numeric value is greater than zero, the result is \f[C]true\f[], else
\f[C]false\f[].
A missing or empty value behind the colon results in a \f[C]null\f[]
JSON element.
.PP
\f[I]jo\f[] creates an array instead of an object when \f[C]\-a\f[] is
specified.
.PP
When the \f[C]:=\f[] operator is used in a \f[I]word\f[], the name to
the right of \f[C]:=\f[] is a file containing JSON which is parsed and
assigned to the key left of the operator.
.SH TYPE COERCION
.PP
\f[I]jo\f[]\[aq]s type guesses can be overridden on a per\-word basis by
prefixing \f[I]word\f[] with \f[C]\-s\f[] for \f[I]string\f[],
\f[C]\-n\f[] for \f[I]number\f[], or \f[C]\-b\f[] for \f[I]boolean\f[].
The list of _word_s \f[I]must\f[] be prefixed with \f[C]\-\-\f[], to
indicate to \f[I]jo\f[] that there are no more global options.
.PP
Type coercion works as follows:
.PP
.TS
tab(@);
l l l l l.
T{
word
T}@T{
\-s
T}@T{
\-n
T}@T{
\-b
T}@T{
default
T}
_
T{
a=
T}@T{
"a":""
T}@T{
"a":0
T}@T{
"a":false
T}@T{
"a":null
T}
T{
a=string
T}@T{
"a":"string"
T}@T{
"a":6
T}@T{
"a":true
T}@T{
"a":"string"
T}
T{
a="quoted"
T}@T{
"a":""quoted""
T}@T{
"a":8
T}@T{
"a":true
T}@T{
"a":""quoted""
T}
T{
a=12345
T}@T{
"a":"12345"
T}@T{
"a":12345
T}@T{
"a":true
T}@T{
"a":12345
T}
T{
a=true
T}@T{
"a":"true"
T}@T{
"a":1
T}@T{
"a":true
T}@T{
"a":true
T}
T{
a=false
T}@T{
"a":"false"
T}@T{
"a":0
T}@T{
"a":false
T}@T{
"a":false
T}
T{
a=null
T}@T{
"a":""
T}@T{
"a":0
T}@T{
"a":false
T}@T{
"a":null
T}
.TE
.PP
Coercing a non\-number string to number outputs the \f[I]length\f[] of
the string.
.PP
Coercing a non\-boolean string to boolean outputs \f[C]false\f[] if the
string is empty, \f[C]true\f[] otherwise.
.PP
Type coercion only applies to \f[C]key=value\f[] words, and individual
words in a \f[C]\-a\f[] array.
Coercing other words has no effect.
.SH EXAMPLES
.PP
Create an object.
Note how the incorrectly\-formatted float value becomes a string:
.IP
.nf
\f[C]
$\ jo\ tst=1457081292\ lat=12.3456\ cc=FR\ badfloat=3.14159.26\ name="JP\ Mens"\ nada=\ coffee\@T
{"tst":1457081292,"lat":12.3456,"cc":"FR","badfloat":"3.14159.26","name":"JP\ Mens","nada":null,"coffee":true}
\f[]
.fi
.PP
Pretty\-print an array with a list of files in the current directory:
.IP
.nf
\f[C]
$\ jo\ \-p\ \-a\ *
[
\ "Makefile",
\ "README.md",
\ "jo.1",
\ "jo.c",
\ "jo.pandoc",
\ "json.c",
\ "json.h"
]
\f[]
.fi
.PP
Create objects within objects; this works because if the first character
of value is an open brace or a bracket we attempt to decode the
remainder as JSON.
Beware spaces in strings ...
.IP
.nf
\f[C]
$\ jo\ \-p\ name=JP\ object=$(jo\ fruit=Orange\ hungry\@0\ point=$(jo\ x=10\ y=20\ list=$(jo\ \-a\ 1\ 2\ 3\ 4\ 5))\ number=17)\ sunday\@0
{
\ "name":\ "JP",
\ "object":\ {
\ \ "fruit":\ "Orange",
\ \ "hungry":\ false,
\ \ "point":\ {
\ \ \ "x":\ 10,
\ \ \ "y":\ 20,
\ \ \ "list":\ [
\ \ \ \ 1,
\ \ \ \ 2,
\ \ \ \ 3,
\ \ \ \ 4,
\ \ \ \ 5
\ \ \ ]
\ \ },
\ \ "number":\ 17
\ },
\ "sunday":\ false
}
\f[]
.fi
.PP
Booleans as strings or as boolean (pay particular attention to
\f[I]switch\f[]; the \f[C]\-B\f[] option disables the default detection
of the "\f[C]true\f[]", "\f[C]false\f[]", and "\f[C]null\f[]" strings):
.IP
.nf
\f[C]
$\ jo\ switch=true\ morning\@0
{"switch":true,"morning":false}
$\ jo\ \-B\ switch=true\ morning\@0
{"switch":"true","morning":false}
\f[]
.fi
.PP
Elements (objects and arrays) can be nested.
The following example nests an array called \f[I]point\f[] and an object
named \f[I]geo\f[]:
.IP
.nf
\f[C]
$\ jo\ \-p\ name=Jane\ point[]=1\ point[]=2\ geo[lat]=10\ geo[lon]=20
{
\ \ \ "name":\ "Jane",
\ \ \ "point":\ [
\ \ \ \ \ \ 1,
\ \ \ \ \ \ 2
\ \ \ ],
\ \ \ "geo":\ {
\ \ \ \ \ \ "lat":\ 10,
\ \ \ \ \ \ "lon":\ 20
\ \ \ }
}
\f[]
.fi
.PP
Type coercion:
.IP
.nf
\f[C]
$\ jo\ \-p\ \-\-\ \-s\ a=true\ b=true\ \-s\ c=123\ d=123\ \-b\ e="1"\ \-b\ f="true"\ \-n\ g="This\ is\ a\ test"\ \-b\ h="This\ is\ a\ test"
{
\ \ \ "a":\ "true",
\ \ \ "b":\ true,
\ \ \ "c":\ "123",
\ \ \ "d":\ 123,
\ \ \ "e":\ true,
\ \ \ "f":\ true,
\ \ \ "g":\ 14,
\ \ \ "h":\ true
}
$\ jo\ \-a\ \-\-\ \-s\ 123\ \-n\ "This\ is\ a\ test"\ \-b\ C_Rocks\ 456
["123",14,true,456]
\f[]
.fi
.PP
Read element values from files: a value which starts with \f[C]\@\f[] is
read in plain whereas if it begins with a \f[C]%\f[] it will be
base64\-encoded:
.IP
.nf
\f[C]
$\ jo\ program=jo\ authors=\@AUTHORS
{"program":"jo","authors":"Jan\-Piet\ Mens\ <jpmens\@gmail.com>"}
$\ jo\ filename=AUTHORS\ content=%AUTHORS
{"filename":"AUTHORS","content":"SmFuLVBpZXQgTWVucyA8anBtZW5zQGdtYWlsLmNvbT4K"}
\f[]
.fi
.PP
Read element values from a file in order to overcome ARG_MAX limits
during object assignment:
.IP
.nf
\f[C]
$\ ls\ |\ jo\ \-a\ >\ child.json
$\ jo\ files:=child.json
{"files":["AUTHORS","COPYING","ChangeLog"\ ....
\f[]
.fi
.SH OPTIONS
.PP
\f[I]jo\f[] understands the following global options.
.TP
.B \-a
Interpret the list of \f[I]words\f[] as array values and produce an
array instead of an object.
.RS
.RE
.TP
.B \-B
By default \f[I]jo\f[] interprets the strings "\f[C]true\f[]" and
"\f[C]false\f[]" as boolean elements \f[C]true\f[] and \f[C]false\f[]
respectively, and "\f[C]null\f[]" as \f[C]null\f[].
Disable with this option.
.RS
.RE
.TP
.B \-p
Pretty\-print the JSON string on output instead of the terse one\-line
output it prints by default.
.RS
.RE
.TP
.B \-v
Show version and exit.
.RS
.RE
.TP
.B \-V
Show version as a JSON object and exit.
.RS
.RE
.SH BUGS
.PP
Probably.
.PP
If a value given to \f[I]jo\f[] expands to empty in the shell, then
\f[I]jo\f[] produces a \f[C]null\f[] in object mode, and might appear to
hang in array mode; it is not hanging, rather it\[aq]s reading
\f[I]stdin\f[].
This is not a bug.
.PP
Numeric values are converted to numbers which can produce undesired
results.
If you quote a numeric value, \f[I]jo\f[] will make it a string.
Compare the following:
.IP
.nf
\f[C]
$\ jo\ a=1.0
{"a":1}
$\ jo\ a=\\"1.0\\"
{"a":"1.0"}
\f[]
.fi
.PP
Omitting a closing bracket on a nested element causes a diagnostic
message to print, but the output contains garbage anyway.
This was designed thusly.
.SH RETURN CODES
.PP
\f[I]jo\f[] exits with a code 0 on success and non\-zero on failure
after indicating what caused the failure.
.SH AVAILABILITY
.PP
<http://github.com/jpmens/jo>
.SH CREDITS
.IP \[bu] 2
This program uses \f[C]json.[ch]\f[], by Joseph A.
Adams.
.SH SEE ALSO
.IP \[bu] 2
<https://stedolan.github.io/jq/>
.IP \[bu] 2
<https://github.com/micha/jsawk>
.IP \[bu] 2
<https://github.com/jtopjian/jsed>
.IP \[bu] 2
strtod(3)
.SH AUTHOR
.PP
Jan\-Piet Mens <http://jpmens.net>
|