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Try the new jc web demo!

JC is now available as an Ansible filter plugin in the community.general collection! See this blog post for an example.

JC

JSON CLI output utility

jc JSONifies the output of many CLI tools and file-types for easier parsing in scripts. See the Parsers section for supported commands and file-types.

This allows further command-line processing of output with tools like jq by piping commands:

ls -l /usr/bin | jc --ls | jq '.[] | select(.size > 50000000)'
{
  "filename": "docker",
  "flags": "-rwxr-xr-x",
  "links": 1,
  "owner": "root",
  "group": "root",
  "size": 68677120,
  "date": "Aug 14 19:41"
}

or using the alternative “magic” syntax:

jc ls -l /usr/bin | jq '.[] | select(.size > 50000000)'
{
  "filename": "docker",
  "flags": "-rwxr-xr-x",
  "links": 1,
  "owner": "root",
  "group": "root",
  "size": 68677120,
  "date": "Aug 14 19:41"
}

The jc parsers can also be used as python modules. In this case the output will be a python dictionary, or list of dictionaries, instead of JSON:

>>> import jc.parsers.ls
>>> 
>>> data='''-rwxr-xr-x  1 root  wheel    23648 May  3 22:26 cat
... -rwxr-xr-x  1 root  wheel    30016 May  3 22:26 chmod
... -rwxr-xr-x  1 root  wheel    29024 May  3 22:26 cp
... -rwxr-xr-x  1 root  wheel   375824 May  3 22:26 csh
... -rwxr-xr-x  1 root  wheel    28608 May  3 22:26 date
... -rwxr-xr-x  1 root  wheel    32000 May  3 22:26 dd
... -rwxr-xr-x  1 root  wheel    23392 May  3 22:26 df
... -rwxr-xr-x  1 root  wheel    18128 May  3 22:26 echo'''
>>>
>>> jc.parsers.ls.parse(data)
[{'filename': 'cat', 'flags': '-rwxr-xr-x', 'links': 1, 'owner': 'root', 'group': 'wheel', 'size': 23648,
'date': 'May 3 22:26'}, {'filename': 'chmod', 'flags': '-rwxr-xr-x', 'links': 1, 'owner': 'root',
'group': 'wheel', 'size': 30016, 'date': 'May 3 22:26'}, {'filename': 'cp', 'flags': '-rwxr-xr-x',
'links': 1, 'owner': 'root', 'group': 'wheel', 'size': 29024, 'date': 'May 3 22:26'}, {'filename': 'csh',
'flags': '-rwxr-xr-x', 'links': 1, 'owner': 'root', 'group': 'wheel', 'size': 375824, 'date': 'May 3
22:26'}, {'filename': 'date', 'flags': '-rwxr-xr-x', 'links': 1, 'owner': 'root', 'group': 'wheel',
'size': 28608, 'date': 'May 3 22:26'}, {'filename': 'dd', 'flags': '-rwxr-xr-x', 'links': 1, 'owner':
'root', 'group': 'wheel', 'size': 32000, 'date': 'May 3 22:26'}, {'filename': 'df', 'flags':
'-rwxr-xr-x', 'links': 1, 'owner': 'root', 'group': 'wheel', 'size': 23392, 'date': 'May 3 22:26'},
{'filename': 'echo', 'flags': '-rwxr-xr-x', 'links': 1, 'owner': 'root', 'group': 'wheel', 'size': 18128,
'date': 'May 3 22:26'}]

Two representations of the data are possible. The default representation uses a strict schema per parser and converts known numbers to int/float JSON values. Certain known values of None are converted to JSON null, known boolean values are converted, and, in some cases, additional semantic context fields are added.

To access the raw, pre-processed JSON, use the -r cli option or the raw=True function parameter in parse().

Schemas for each parser can be found in the docs/parsers folder.

Release notes can be found here.

Why Would Anyone Do This!?

For more information on the motivations for this project, please see my blog post.

See also:

Installation

There are several ways to get jc. You can install via pip; other OS package repositories like apt-get, dnf, zypper, pacman, nix-env, guix, brew, or portsnap; via DEB/RPM packages; or by downloading the correct binary for your architecture and running it anywhere on your filesystem.

Pip (macOS, linux, unix, Windows)

pip3 install jc

OS Package Repositories

OS Command
Debian linux apt-get install jc
Fedora linux dnf install jc
openSUSE linux zypper install jc
Arch linux pacman -S jc
NixOS linux nix-env -iA nixpkgs.jc
Guix System linux guix install jc
MacOS brew install jc
FreeBSD portsnap fetch update && cd /usr/ports/textproc/py-jc && make install clean
Ansible filter plugin ansible-galaxy collection install community.general

For more packages and binaries, see https://kellyjonbrazil.github.io/jc-packaging/.

Usage

jc accepts piped input from STDIN and outputs a JSON representation of the previous command’s output to STDOUT.

COMMAND | jc PARSER [OPTIONS]

Alternatively, the “magic” syntax can be used by prepending jc to the command to be converted. Options can be passed to jc immediately before the command is given. (Note: command aliases are not supported)

jc [OPTIONS] COMMAND

The JSON output can be compact (default) or pretty formatted with the -p option.

Parsers

Options

Setting Custom Colors via Environment Variable

You can specify custom colors via the JC_COLORS environment variable. The JC_COLORS environment variable takes four comma separated string values in the following format:

JC_COLORS=<keyname_color>,<keyword_color>,<number_color>,<string_color>

Where colors are: black, red, green, yellow, blue, magenta, cyan, gray, brightblack, brightred, brightgreen, brightyellow, brightblue, brightmagenta, brightcyan, white, or default

For example, to set to the default colors:

JC_COLORS=blue,brightblack,magenta,green

or

JC_COLORS=default,default,default,default

Custom Parsers

Custom local parser plugins may be placed in a jc/jcparsers folder in your local “App data directory”:

Local parser plugins are standard python module files. Use the jc/parsers/foo.py parser as a template and simply place a .py file in the jcparsers subfolder.

Local plugin filenames must be valid python module names, therefore must consist entirely of alphanumerics and start with a letter. Local plugins may override default plugins.

Note: The application data directory follows the XDG Base Directory Specification

Compatibility

Some parsers like ls, ps, dig, etc. will work on any platform. Other parsers that are platform-specific will generate a warning message if they are used on an unsupported platform. To see all parser information, including compatibility, run jc -ap.

You may still use a parser on an unsupported platform - for example, you may want to parse a file with linux lsof output on an OSX laptop. In that case you can suppress the warning message with the -q cli option or the quiet=True function parameter in parse():

cat lsof.out | jc --lsof -q

Tested on:

Contributions

Feel free to add/improve code or parsers! You can use the jc/parsers/foo.py parser as a template and submit your parser with a pull request.

Acknowledgments

Examples

Here are some examples of jc output. For more examples, see EXAMPLES.md or the parser documentation.

arp

arp | jc --arp -p          # or:  jc -p arp
[
  {
    "address": "gateway",
    "hwtype": "ether",
    "hwaddress": "00:50:56:f7:4a:fc",
    "flags_mask": "C",
    "iface": "ens33"
  },
  {
    "address": "192.168.71.1",
    "hwtype": "ether",
    "hwaddress": "00:50:56:c0:00:08",
    "flags_mask": "C",
    "iface": "ens33"
  },
  {
    "address": "192.168.71.254",
    "hwtype": "ether",
    "hwaddress": "00:50:56:fe:7a:b4",
    "flags_mask": "C",
    "iface": "ens33"
  }
]

CSV files

cat homes.csv
"Sell", "List", "Living", "Rooms", "Beds", "Baths", "Age", "Acres", "Taxes"
142, 160, 28, 10, 5, 3,  60, 0.28,  3167
175, 180, 18,  8, 4, 1,  12, 0.43,  4033
129, 132, 13,  6, 3, 1,  41, 0.33,  1471
...
cat homes.csv | jc --csv -p
[
  {
    "Sell": "142",
    "List": "160",
    "Living": "28",
    "Rooms": "10",
    "Beds": "5",
    "Baths": "3",
    "Age": "60",
    "Acres": "0.28",
    "Taxes": "3167"
  },
  {
    "Sell": "175",
    "List": "180",
    "Living": "18",
    "Rooms": "8",
    "Beds": "4",
    "Baths": "1",
    "Age": "12",
    "Acres": "0.43",
    "Taxes": "4033"
  },
  {
    "Sell": "129",
    "List": "132",
    "Living": "13",
    "Rooms": "6",
    "Beds": "3",
    "Baths": "1",
    "Age": "41",
    "Acres": "0.33",
    "Taxes": "1471"
  }
]

dig

dig cnn.com @205.251.194.64 | jc --dig -p          # or:  jc -p dig cnn.com @205.251.194.64
[
  {
    "id": 5509,
    "opcode": "QUERY",
    "status": "NOERROR",
    "flags": [
      "qr",
      "rd",
      "ra"
    ],
    "query_num": 1,
    "answer_num": 1,
    "authority_num": 0,
    "additional_num": 1,
    "question": {
      "name": "cnn.com.",
      "class": "IN",
      "type": "A"
    },
    "answer": [
      {
        "name": "cnn.com.",
        "class": "IN",
        "type": "A",
        "ttl": 60,
        "data": "151.101.129.67"
      }
    ],
    "query_time": 28,
    "server": "2600",
    "when": "Tue Nov 12 07:13:03 PST 2019",
    "rcvd": 100
  }
]

/etc/hosts file

cat /etc/hosts | jc --hosts -p
[
  {
    "ip": "127.0.0.1",
    "hostname": [
      "localhost"
    ]
  },
  {
    "ip": "::1",
    "hostname": [
      "ip6-localhost",
      "ip6-loopback"
    ]
  },
  {
    "ip": "fe00::0",
    "hostname": [
      "ip6-localnet"
    ]
  }
]

ifconfig

ifconfig | jc --ifconfig -p          # or:  jc -p ifconfig
[
  {
    "name": "ens33",
    "flags": 4163,
    "state": [
      "UP",
      "BROADCAST",
      "RUNNING",
      "MULTICAST"
    ],
    "mtu": 1500,
    "ipv4_addr": "192.168.71.137",
    "ipv4_mask": "255.255.255.0",
    "ipv4_bcast": "192.168.71.255",
    "ipv6_addr": "fe80::c1cb:715d:bc3e:b8a0",
    "ipv6_mask": 64,
    "ipv6_scope": "0x20",
    "mac_addr": "00:0c:29:3b:58:0e",
    "type": "Ethernet",
    "rx_packets": 8061,
    "rx_bytes": 1514413,
    "rx_errors": 0,
    "rx_dropped": 0,
    "rx_overruns": 0,
    "rx_frame": 0,
    "tx_packets": 4502,
    "tx_bytes": 866622,
    "tx_errors": 0,
    "tx_dropped": 0,
    "tx_overruns": 0,
    "tx_carrier": 0,
    "tx_collisions": 0,
    "metric": null
  }
]

INI files

cat example.ini
[DEFAULT]
ServerAliveInterval = 45
Compression = yes
CompressionLevel = 9
ForwardX11 = yes

[bitbucket.org]
User = hg

[topsecret.server.com]
Port = 50022
ForwardX11 = no
cat example.ini | jc --ini -p
{
  "bitbucket.org": {
    "serveraliveinterval": "45",
    "compression": "yes",
    "compressionlevel": "9",
    "forwardx11": "yes",
    "user": "hg"
  },
  "topsecret.server.com": {
    "serveraliveinterval": "45",
    "compression": "yes",
    "compressionlevel": "9",
    "forwardx11": "no",
    "port": "50022"
  }
}

ls

$ ls -l /usr/bin | jc --ls -p          # or:  jc -p ls -l /usr/bin
[
  {
    "filename": "apropos",
    "link_to": "whatis",
    "flags": "lrwxrwxrwx.",
    "links": 1,
    "owner": "root",
    "group": "root",
    "size": 6,
    "date": "Aug 15 10:53"
  },
  {
    "filename": "ar",
    "flags": "-rwxr-xr-x.",
    "links": 1,
    "owner": "root",
    "group": "root",
    "size": 62744,
    "date": "Aug 8 16:14"
  },
  {
    "filename": "arch",
    "flags": "-rwxr-xr-x.",
    "links": 1,
    "owner": "root",
    "group": "root",
    "size": 33080,
    "date": "Aug 19 23:25"
  }
]

netstat

netstat -apee | jc --netstat -p          # or:  jc -p netstat -apee
[
  {
    "proto": "tcp",
    "recv_q": 0,
    "send_q": 0,
    "local_address": "localhost",
    "foreign_address": "0.0.0.0",
    "state": "LISTEN",
    "user": "systemd-resolve",
    "inode": 26958,
    "program_name": "systemd-resolve",
    "kind": "network",
    "pid": 887,
    "local_port": "domain",
    "foreign_port": "*",
    "transport_protocol": "tcp",
    "network_protocol": "ipv4"
  },
  {
    "proto": "tcp6",
    "recv_q": 0,
    "send_q": 0,
    "local_address": "[::]",
    "foreign_address": "[::]",
    "state": "LISTEN",
    "user": "root",
    "inode": 30510,
    "program_name": "sshd",
    "kind": "network",
    "pid": 1186,
    "local_port": "ssh",
    "foreign_port": "*",
    "transport_protocol": "tcp",
    "network_protocol": "ipv6"
  },
  {
    "proto": "udp",
    "recv_q": 0,
    "send_q": 0,
    "local_address": "localhost",
    "foreign_address": "0.0.0.0",
    "state": null,
    "user": "systemd-resolve",
    "inode": 26957,
    "program_name": "systemd-resolve",
    "kind": "network",
    "pid": 887,
    "local_port": "domain",
    "foreign_port": "*",
    "transport_protocol": "udp",
    "network_protocol": "ipv4"
  },
  {
    "proto": "raw6",
    "recv_q": 0,
    "send_q": 0,
    "local_address": "[::]",
    "foreign_address": "[::]",
    "state": "7",
    "user": "systemd-network",
    "inode": 27001,
    "program_name": "systemd-network",
    "kind": "network",
    "pid": 867,
    "local_port": "ipv6-icmp",
    "foreign_port": "*",
    "transport_protocol": null,
    "network_protocol": "ipv6"
  },
  {
    "proto": "unix",
    "refcnt": 2,
    "flags": null,
    "type": "DGRAM",
    "state": null,
    "inode": 33322,
    "program_name": "systemd",
    "path": "/run/user/1000/systemd/notify",
    "kind": "socket",
    "pid": 1607
  }
]

/etc/passwd file

cat /etc/passwd | jc --passwd -p
[
  {
    "username": "root",
    "password": "*",
    "uid": 0,
    "gid": 0,
    "comment": "System Administrator",
    "home": "/var/root",
    "shell": "/bin/sh"
  },
  {
    "username": "daemon",
    "password": "*",
    "uid": 1,
    "gid": 1,
    "comment": "System Services",
    "home": "/var/root",
    "shell": "/usr/bin/false"
  }
]

ping

ping 8.8.8.8 -c 3 | jc --ping -p          # or:  jc -p ping 8.8.8.8 -c 3
{
  "destination_ip": "8.8.8.8",
  "data_bytes": 56,
  "pattern": null,
  "destination": "8.8.8.8",
  "packets_transmitted": 3,
  "packets_received": 3,
  "packet_loss_percent": 0.0,
  "duplicates": 0,
  "time_ms": 2005.0,
  "round_trip_ms_min": 23.835,
  "round_trip_ms_avg": 30.46,
  "round_trip_ms_max": 34.838,
  "round_trip_ms_stddev": 4.766,
  "responses": [
    {
      "type": "reply",
      "timestamp": null,
      "bytes": 64,
      "response_ip": "8.8.8.8",
      "icmp_seq": 1,
      "ttl": 118,
      "time_ms": 23.8,
      "duplicate": false
    },
    {
      "type": "reply",
      "timestamp": null,
      "bytes": 64,
      "response_ip": "8.8.8.8",
      "icmp_seq": 2,
      "ttl": 118,
      "time_ms": 34.8,
      "duplicate": false
    },
    {
      "type": "reply",
      "timestamp": null,
      "bytes": 64,
      "response_ip": "8.8.8.8",
      "icmp_seq": 3,
      "ttl": 118,
      "time_ms": 32.7,
      "duplicate": false
    }
  ]
}

ps

ps axu | jc --ps -p          # or:  jc -p ps axu
[
  {
    "user": "root",
    "pid": 1,
    "cpu_percent": 0.0,
    "mem_percent": 0.1,
    "vsz": 128072,
    "rss": 6784,
    "tty": null,
    "stat": "Ss",
    "start": "Nov09",
    "time": "0:08",
    "command": "/usr/lib/systemd/systemd --switched-root --system --deserialize 22"
  },
  {
    "user": "root",
    "pid": 2,
    "cpu_percent": 0.0,
    "mem_percent": 0.0,
    "vsz": 0,
    "rss": 0,
    "tty": null,
    "stat": "S",
    "start": "Nov09",
    "time": "0:00",
    "command": "[kthreadd]"
  },
  {
    "user": "root",
    "pid": 4,
    "cpu_percent": 0.0,
    "mem_percent": 0.0,
    "vsz": 0,
    "rss": 0,
    "tty": null,
    "stat": "S<",
    "start": "Nov09",
    "time": "0:00",
    "command": "[kworker/0:0H]"
  }
]

traceroute

traceroute -m 2 8.8.8.8 | jc --traceroute -p          # or:  jc -p traceroute -m 2 8.8.8.8
{
  "destination_ip": "8.8.8.8",
  "destination_name": "8.8.8.8",
  "hops": [
    {
      "hop": 1,
      "probes": [
        {
          "annotation": null,
          "asn": null,
          "ip": "192.168.1.254",
          "name": "dsldevice.local.net",
          "rtt": 6.616
        },
        {
          "annotation": null,
          "asn": null,
          "ip": "192.168.1.254",
          "name": "dsldevice.local.net",
          "rtt": 6.413
        },
        {
          "annotation": null,
          "asn": null,
          "ip": "192.168.1.254",
          "name": "dsldevice.local.net",
          "rtt": 6.308
        }
      ]
    },
    {
      "hop": 2,
      "probes": [
        {
          "annotation": null,
          "asn": null,
          "ip": "76.220.24.1",
          "name": "76-220-24-1.lightspeed.sntcca.sbcglobal.net",
          "rtt": 29.367
        },
        {
          "annotation": null,
          "asn": null,
          "ip": "76.220.24.1",
          "name": "76-220-24-1.lightspeed.sntcca.sbcglobal.net",
          "rtt": 40.197
        },
        {
          "annotation": null,
          "asn": null,
          "ip": "76.220.24.1",
          "name": "76-220-24-1.lightspeed.sntcca.sbcglobal.net",
          "rtt": 29.162
        }
      ]
    }
  ]
}

uptime

uptime | jc --uptime -p          # or:  jc -p uptime
{
  "time": "11:30:44",
  "uptime": "1 day, 21:17",
  "users": 1,
  "load_1m": 0.01,
  "load_5m": 0.04,
  "load_15m": 0.05
}

XML files

cat cd_catalog.xml
<?xml version="1.0" encoding="UTF-8"?>
<CATALOG>
  <CD>
    <TITLE>Empire Burlesque</TITLE>
    <ARTIST>Bob Dylan</ARTIST>
    <COUNTRY>USA</COUNTRY>
    <COMPANY>Columbia</COMPANY>
    <PRICE>10.90</PRICE>
    <YEAR>1985</YEAR>
  </CD>
  <CD>
    <TITLE>Hide your heart</TITLE>
    <ARTIST>Bonnie Tyler</ARTIST>
    <COUNTRY>UK</COUNTRY>
    <COMPANY>CBS Records</COMPANY>
    <PRICE>9.90</PRICE>
    <YEAR>1988</YEAR>
  </CD>
  ...
cat cd_catalog.xml | jc --xml -p
{
  "CATALOG": {
    "CD": [
      {
        "TITLE": "Empire Burlesque",
        "ARTIST": "Bob Dylan",
        "COUNTRY": "USA",
        "COMPANY": "Columbia",
        "PRICE": "10.90",
        "YEAR": "1985"
      },
      {
        "TITLE": "Hide your heart",
        "ARTIST": "Bonnie Tyler",
        "COUNTRY": "UK",
        "COMPANY": "CBS Records",
        "PRICE": "9.90",
        "YEAR": "1988"
      }
    ]
  }
}

YAML files

cat istio.yaml 
apiVersion: "authentication.istio.io/v1alpha1"
kind: "Policy"
metadata:
  name: "default"
  namespace: "default"
spec:
  peers:
  - mtls: {}
---
apiVersion: "networking.istio.io/v1alpha3"
kind: "DestinationRule"
metadata:
  name: "default"
  namespace: "default"
spec:
  host: "*.default.svc.cluster.local"
  trafficPolicy:
    tls:
      mode: ISTIO_MUTUAL
cat istio.yaml | jc --yaml -p
[
  {
    "apiVersion": "authentication.istio.io/v1alpha1",
    "kind": "Policy",
    "metadata": {
      "name": "default",
      "namespace": "default"
    },
    "spec": {
      "peers": [
        {
          "mtls": {}
        }
      ]
    }
  },
  {
    "apiVersion": "networking.istio.io/v1alpha3",
    "kind": "DestinationRule",
    "metadata": {
      "name": "default",
      "namespace": "default"
    },
    "spec": {
      "host": "*.default.svc.cluster.local",
      "trafficPolicy": {
        "tls": {
          "mode": "ISTIO_MUTUAL"
        }
      }
    }
  }
]