jq json filter and keep original structure

Question

I am really new to the command jq, and I am trying do some filtering to remove blocks of data that I don't want/need.

Here is an example of my JSON structure:

{
  "BackupCfg": [
    {
      "type": "filesystem",
      "repository": "trunk",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "Default": "true",
          "ID": "trunk00",
          "Paths": [
            "/etc",
            "/home",
            "/var",
            "/usr/local",
            "/opt",
            "/root"
          ],
          "Cron": "33 0 * * *"
        }
      ]
    },
    {
      "type": "filesystem",
      "repository": "trunk02",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "ID": "trunk01",
          "Paths": [
            "/opt/example",
            "/opt/var_example"
          ],
          "Cron": "*/30 0-23 * * *"
        }
      ]
    },
    {
      "type": "database",
      "repository": "trunk-db",
      "url": "test.example.com",
      "port": "399",
      "cfg": [
        {
          "Default": "true",
          "ID": "trunk00",
          "db_type": "mysql",
          "db_hostname": "localhost",
          "db_port": "3306",
          "db_user": "root",
          "db_pwd": "password",
          "databases": [],
          "Cron": "40 0 * * *"
        },
        {
          "ID": "trunk01",
          "db_type": "mysql",
          "db_hostname": "localhost",
          "db_port": "3307",
          "db_user": "riit",
          "db_pwd": "passwird",
          "databases": [],
          "Cron": "33 3 * * *"
        },
        {
          "Default": "false",
          "ID": "trunk02",
          "db_type": "postgres",
          "db_hostname": "localhost",
          "db_port": "3308",
          "db_user": "ruut",
          "db_pwd": "passwurd",
          "databases": [],
          "Cron": "0 10 * * *"
        }
      ]
    }
  ]
}

I want to filter this in order to have only the "type": "filesystem", and get the following output:

{
  "BackupCfg": [
    {
      "type": "filesystem",
      "repository": "trunk",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "Default": "true",
          "ID": "trunk00",
          "Paths": [
            "/etc",
            "/home",
            "/var",
            "/usr/local",
            "/opt",
            "/root"
          ],
          "Cron": "33 0 * * *"
        }
      ]
    },
    {
      "type": "filesystem",
      "repository": "trunk02",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "ID": "trunk01",
          "Paths": [
            "/opt/example",
            "/opt/var_example"
          ],
          "Cron": "*/30 0-23 * * *"
        }
      ]
    }
  ]
}

I have try some commands like

jq  '.[][] | select(.type | contains("filesystem"))'

But it destroys the original structure.

I have searched around, and found lots of example, but lots doesn't work, or doesn't give me what I need.

Has someone any ideas? If someone has also any good learning website in order to understand jq, that would be awesome!

Thanks in advance!

Would you mind simplifying your question by creating a "Minimal, Complete, and Verifiable example". I do appreciate the question very much, but I don't want to read your entire json object structure to make sense of it! — markling, Feb 23 '21 at 11:28

score 8 · Accepted Answer · answered Feb 26 '18 at 22:17

jq solution:

jq '.BackupCfg |= map(select(.type == "filesystem"))' file.json

The output:

{
  "BackupCfg": [
    {
      "type": "filesystem",
      "repository": "trunk",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "Default": "true",
          "ID": "trunk00",
          "Paths": [
            "/etc",
            "/home",
            "/var",
            "/usr/local",
            "/opt",
            "/root"
          ],
          "Cron": "33 0 * * *"
        }
      ]
    },
    {
      "type": "filesystem",
      "repository": "trunk02",
      "url": "test.example.com",
      "port": "394",
      "cfg": [
        {
          "ID": "trunk01",
          "Paths": [
            "/opt/example",
            "/opt/var_example"
          ],
          "Cron": "*/30 0-23 * * *"
        }
      ]
    }
  ]
}

https://stedolan.github.io/jq/manual/v1.5/#select(boolean_expression)

Wow, I think that the trick here was to use the operator |= I didn't know that operator! I am reading it now. — Alessandro Perucchi, Feb 26 '18 at 22:36

jq json filter and keep original structure

1 Answers1