jq命令 - json文本处理

#CentOS
yum install jq

#MacOS
brew install jq

cat json.txt
[{"genre":"deep house"}, {"genre": "progressive house"}, {"genre": "dubstep"}]

cat json.txt | jq '.' 

[
  {
    "genre": "deep house"
  },
  {
    "genre": "progressive house"
  },
  {
    "genre": "dubstep"
  }
]

cat json.txt | jq '.[0]'

{
  "genre": "deep house"
}

jq '.[0].genre' json.txt

"deep house"

cat json.txt| jq -c '[.[] | {"name", "age"}]'
[{"name":"tenmao","age":100},{"name":"tencent","age":null}]

cat json.txt| jq -c 'map(select(.name == "tenmao"))'
[{"genre":"deep house","name":"tenmao","age":100}]

# 使用map: 映射， 其中.号表示原文， + 表示merge信息
# if then else end是逻辑语句
cat json.txt| jq -c 'map(if .name == "tenmao" then . + {hobby: "baskball"} else . end)'
[{"genre":"deep house","name":"tenmao","age":100,"hobby":"baskball"},{"genre":"progressive house","name":"tencent"}]