Linux JSON 处理工具 jq

这里的 jq 可不是曾经的前端利器 jQuery。

jq是一个出色的命令行针对JSON处理器，提供了用于查询、操作和使用JSON文件的大量功能，而且作为一个命令行工具，可配合UNIX管道使用，单行脚本处理JSON；

jq可以对json数据进行分片、过滤、映射、转换；和sed、awk、grep等命令一样，可以让你轻松地把玩文本；它能轻松地把你拥有的数据’转换成’你期望的格式，而且需要写的程序通常也比你期望的更加简短。

安装 jq

你可以用市面上的各种包管理器来安装 jq，例如 linux 的 apt-get、OS X 的 HomeBrew等，如果安装失败或者找不到包，把包管理器升级一下再试试。

$ apt-get install jq -y
$ brew install jq
$ yum install jq
$ chocolatey install jq
# ......

语法

jq 的使用场景大多是通过管道的形式来对数据进行过滤或者增强等操作

❯ jq –help
jq - commandline JSON processor [version 1.6]

Usage: jq [options] [file…]
jq [options] –args [strings…]
jq [options] –jsonargs [JSON_TEXTS…]

jq is a tool for processing JSON inputs, applying the given filter to
its JSON text inputs and producing the filter’s results as JSON on
standard output.

The simplest filter is ., which copies jq’s input to its output
unmodified (except for formatting, but note that IEEE754 is used
for number representation internally, with all that that implies).

For more advanced filters see the jq(1) manpage (“man jq”)
and/or https://stedolan.github.io/jq

Example:
$ echo '{"foo": 0}' | jq .
{
    "foo": 0
}
Some of the options include:
-c compact instead of pretty-printed output;
-n use null as the single input value;
-e set the exit status code based on the output;
-s read (slurp) all inputs into an array; apply filter to it;
-r output raw strings, not JSON texts;
-R read raw strings, not JSON texts;
-C colorize JSON;
-M monochrome (don’t colorize JSON);
-S sort keys of objects on output;
–tab use tabs for indentation;
–arg a v set variable $a to value ;
–argjson a v set variable $a to JSON value ;
–slurpfile a f set variable $a to an array of JSON texts read from ;
–rawfile a f set variable $a to a string consisting of the contents of ;
–args remaining arguments are string arguments, not files;
–jsonargs remaining arguments are JSON arguments, not files;
– terminates argument processing;

Named arguments are also available as $ARGS.named[], while
positional arguments are available as $ARGS.positional[].

See the manpage for more options.