bash: shell table output to json

| Created | Modified

This post presents a Python script that converts tabular command-line output into a more versatile JSON format. This allows for easier data manipulation using tools like jq, as an alternative to complex text-processing pipelines in bash.

You know that sometimes it would be really great to format a shell output to a more versatile format like JSON or YAML that you can process with jq instead of writing long pipes with text-processing.

Ah yeah, you could use python instead of bash ;)

Before

$ virsh net-list
 Name                 State      Autostart     Persistent
----------------------------------------------------------
 default              active     yes           yes

After

$ virsh net-list | table-to-json
[
    {
        "autostart": "yes",
        "name": "default",
        "persistent": "yes",
        "state": "active"
    }
]

$ virsh net-list | bin/table-to-json  | jq -r ".[0].name"
default

table-to-json

#!/usr/bin/env python

import sys
import re
import json

def parse_line(line):
    if line.find("\t") == -1:
        line = re.sub(r'\s+', '\t', line , flags=re.IGNORECASE)
    line = re.sub(r'^\s+', '', line , flags=re.IGNORECASE)
    line = re.sub(r'\s+$', '', line , flags=re.IGNORECASE)
    return [x for x in line.split("\t") if x]

lastparts = []
columns = None
data = []
for line in sys.stdin:
    parts = parse_line(line)
    if len(parts)>0:
        if len(parts)>0 and parts[0].startswith("-"):
            columns=[x.lower() for x in lastparts]
        elif len(parts)>0 and columns:
            data.append(dict(zip(columns, parts)))
    lastparts = parts

print(json.dumps(data, sort_keys=True, indent=4))

UPDATE: Maybe the script should use asciitable.