jtbl

A simple cli tool to print JSON data as a table in the terminal.

jtbl accepts piped JSON data from stdin and outputs a text table representation to stdout. e.g:

$ cat cities.json | jtbl 
  LatD    LatM    LatS  NS      LonD    LonM    LonS  EW    City               State
------  ------  ------  ----  ------  ------  ------  ----  -----------------  -------
    41       5      59  N         80      39       0  W     Youngstown         OH
    42      52      48  N         97      23      23  W     Yankton            SD
    46      35      59  N        120      30      36  W     Yakima             WA
    42      16      12  N         71      48       0  W     Worcester          MA
    43      37      48  N         89      46      11  W     Wisconsin Dells    WI
    36       5      59  N         80      15       0  W     Winston-Salem      NC
    49      52      48  N         97       9       0  W     Winnipeg           MB

jtbl expects a JSON array of JSON objects or JSON Lines.

It can be useful to JSONify command line output with jc, filter through a tool like jq, and present in jtbl:

$ jc ifconfig | jq -c '.[] | {name, type, ipv4_addr, ipv4_mask}'| jtbl 
name     type            ipv4_addr       ipv4_mask
-------  --------------  --------------  -------------
docker0  Ethernet        172.17.0.1      255.255.0.0
ens33    Ethernet        192.168.71.146  255.255.255.0
lo       Local Loopback  127.0.0.1       255.0.0.0

Installation

pip3 install --upgrade jtbl

Usage

Just pipe JSON data to jtbl. (e.g. cat a JSON file, jc, jq, aws cli, kubectl, etc.)

$ <JSON Data> | jtbl [OPTIONS]

Options

• --cols=n manually configure the terminal width
• -n no data wrapping if too long for the terminal width (overrides --cols and -t)
• -t truncate data instead of wrapping if too long for the terminal width
• -v prints version information
• -h prints help information

Compatible JSON Formats

jtbl works best with a shallow array of JSON objects. Each object should have a few elements that will be turned into table columns. Fortunately, this is how many APIs present their data.

JSON Array Example

[
  {
    "unit": "proc-sys-fs-binfmt_misc.automount",
    "load": "loaded",
    "active": "active",
    "sub": "waiting",
    "description": "Arbitrary Executable File Formats File System Automount Point"
  },
  {
    "unit": "sys-devices-pci0000:00-0000:00:07.1-ata2-host2-target2:0:0-2:0:0:0-block-sr0.device",
    "load": "loaded",
    "active": "active",
    "sub": "plugged",
    "description": "VMware_Virtual_IDE_CDROM_Drive"
  },
  ...
]

jtbl can also work with JSON Lines format with similar features.

JSON Lines Example

{"name": "docker0", type": "Ethernet", "ipv4_addr": "172.17.0.1", "ipv4_mask": "255.255.0.0"}
{"name": "ens33", "type": "Ethernet", "ipv4_addr": "192.168.71.146", "ipv4_mask": "255.255.255.0"}
{"name": "lo", "type": "Local Loopback", "ipv4_addr": "127.0.0.1", "ipv4_mask": "255.0.0.0"}
...

Filtering the JSON Input

If there are too many elements, or the data in the elements are too large, the table may not fit in the terminal screen. In this case you can use a JSON filter like jq or jello to send jtbl only the elements you are interested in:

jq Array Method

The following example uses jq to filter and format the filtered elements into a proper JSON array.

$ cat /etc/passwd | jc --passwd | jq '[.[] | {username, shell}]'
[
  {
    "username": "root",
    "shell": "/bin/bash"
  },
  {
    "username": "bin",
    "shell": "/sbin/nologin"
  },
  {
    "username": "daemon",
    "shell": "/sbin/nologin"
  },
  ...
]

(Notice the square brackets around the filter)

jq Slurp Method

The following example uses jq to filter and 'slurp' the filtered elements into a proper JSON array.

$ cat /etc/passwd | jc --passwd | jq '.[] | {username, shell}' | jq -s
[
  {
    "username": "root",
    "shell": "/bin/bash"
  },
  {
    "username": "bin",
    "shell": "/sbin/nologin"
  },
  {
    "username": "daemon",
    "shell": "/sbin/nologin"
  },
  ...
]

(Notice the jq -s at the end)

jq JSON Lines Method

The following example will send the data in JSON Lines format, which jtbl can understand:

$ cat /etc/passwd | jc --passwd | jq -c '.[] | {username, shell}'
{"username":"root","shell":"/bin/bash"}
{"username":"bin","shell":"/sbin/nologin"}
{"username":"daemon","shell":"/sbin/nologin"}
...

(Notice the -c option being used)

jello List Comprehension Method

If you prefer python list and dictionary syntax to filter JSON data, you can use jello:

$ cat /etc/passwd | jc --passwd | jello '[{"username": x["username"], "shell": x["shell"]} for x in _]'
[
  {
    "username": "root",
    "shell": "/bin/bash"
  },
  {
    "username": "bin",
    "shell": "/sbin/nologin"
  },
  {
    "username": "daemon",
    "shell": "/sbin/nologin"
  },
  ...
]

When piping any of these to jtbl you get the following result:

$ cat /etc/passwd | jc --passwd | jello '[{"username": x["username"], "shell": x["shell"]} for x in _]' | jtbl
username         shell
---------------  --------------
root             /bin/bash
bin              /sbin/nologin
daemon           /sbin/nologin
...

Working with Deeper JSON Structures

jtbl will happily dump deeply nested JSON structures into a table, but usually this is not what you are looking for.

$ jc dig www.cnn.com | jtbl
+-------+----------+----------+--------------+-------------+--------------+-----------------+------------------+--------------+--------------+--------------+----------+--------------+--------+
|    id | opcode   | status   | flags        |   query_num |   answer_num |   authority_num |   additional_num | question     | answer       |   query_time |   server | when         |   rcvd |
+=======+==========+==========+==============+=============+==============+=================+==================+==============+==============+==============+==========+==============+========+
| 28791 | QUERY    | NOERROR  | ['qr', 'rd', |           1 |            5 |               0 |                1 | {'name': 'ww | [{'name': 'w |           32 |     2600 | Fri Mar 06 1 |    143 |
|       |          |          |  'ra']       |             |              |                 |                  | w.cnn.com.', | ww.cnn.com.' |              |          | 7:15:25 PST  |        |
|       |          |          |              |             |              |                 |                  |  'class': 'I | , 'class': ' |              |          | 2020         |        |
|       |          |          |              |             |              |                 |                  | N', 'type':  | IN', 'type': |              |          |              |        |
|       |          |          |              |             |              |                 |                  | 'A'}         |  'CNAME', 't |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | tl': 251, 'd |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | ata': 'turne |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | r-tls.map.fa |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | stly.net.'}, |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              |  {'name': 't |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | urner-tls.ma |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | p.fastly.net |              |          |              |        |
|       |          |          |              |             |              |                 |                  |              | ...          |              |          |              |        |
+-------+----------+----------+--------------+-------------+--------------+-----------------+------------------+--------------+--------------+--------------+----------+--------------+--------+

Diving Deeper into the JSON with jq or jello:

To get to the data you are interested in you can use a JSON filter like jq or jello to dive deeper.

Using jq:

$ jc dig www.cnn.com | jq '.[0].answer' 

or with jello:

$ jc dig www.cnn.com | jello '_[0]["answer"]'

Both will produce the following output:

[
  {
    "name": "www.cnn.com.",
    "class": "IN",
    "type": "CNAME",
    "ttl": 90,
    "data": "turner-tls.map.fastly.net."
  },
  {
    "name": "turner-tls.map.fastly.net.",
    "class": "IN",
    "type": "A",
    "ttl": 20,
    "data": "151.101.1.67"
  }
  ...
]

This will produce the following table in jtbl

$ jc dig www.cnn.com | jello '_[0]["answer"]' | jtbl
name                        class    type      ttl  data
--------------------------  -------  ------  -----  --------------------------
www.cnn.com.                IN       CNAME      11  turner-tls.map.fastly.net.
turner-tls.map.fastly.net.  IN       A          23  151.101.129.67
turner-tls.map.fastly.net.  IN       A          23  151.101.1.67
turner-tls.map.fastly.net.  IN       A          23  151.101.65.67
turner-tls.map.fastly.net.  IN       A          23  151.101.193.67

Column Width

jtbl will attempt to shrink columns to a sane size if it detects the output is wider than the terminal width. The --cols option will override the automatic terminal width detection.

You can use the -t option to truncate the rows instead of wrapping when the terminal width is too small for all of the data.

The -n option disables wrapping and overrides the --cols and -t options.

This can be useful to present a nicely non-wrapped table of infinite width in combination with less -S:

$ jc ps aux | jtbl -n | less -S
user                  pid        vsz     rss  tt    stat    started    time       command                                            
------------------  -----  ---------  ------  ----  ------  ---------  ---------  ---------------------------------------------------
joeuser             34029    4277364   24800  s000  S+      9:28AM     0:00.27    /usr/local/Cellar/python/3.7.6_1/Frameworks/Python....
joeuser             34030    4283136   17104  s000  S+      9:28AM     0:00.20    /usr/local/Cellar/python/3.7.6_1/Frameworks/Python....
joeuser               481    5728568  189328        S       17Apr20    21:46.52   /Applications/Utilities/Terminal.app/Contents/MacOS...
joeuser             45827    6089084  693768        S       Wed01PM    84:54.87   /Applications/Microsoft Teams.app/Contents/Framewor...
joeuser              1493    9338824  911600        S       17Apr20    143:27.08  /Applications/Microsoft Outlook.app/Contents/MacOS/...
joeuser             45822    5851524  163840        S       Wed01PM    38:48.83   /Applications/Microsoft Teams.app/Contents/MacOS/Te...