Bash에서 JSON 포맷하는 방법: jq 완전 가이드

# macOS
brew install jq

# Debian / Ubuntu
apt-get install -y jq

# Fedora / RHEL / CentOS
dnf install jq

# Alpine (Docker images)
apk add --no-cache jq

# Verify
jq --version  # jq-1.7.1

# Pipe inline JSON through jq
echo '{"host":"db-prod-01.internal","port":5432}' | jq .

# Format a file directly (prints to stdout)
jq . config/feature-flags.json

# Format with 4-space indentation
jq --indent 4 . config/feature-flags.json

# Format using tabs instead of spaces
jq --tab . config/feature-flags.json

# Save formatted output (do NOT redirect back to the same file)
jq . compact.json > formatted.json

# Compact (minify) — reverse of formatting
jq -c . formatted.json

# Sort all keys alphabetically (useful for deterministic diffs)
jq --sort-keys . config/app-config.json

# Disable colour output when writing to a log file
jq --monochrome-output . response.json >> deploy.log

validate_json() {
  local file="$1"
  if jq . "$file" > /dev/null 2>&1; then
    echo "✓ Valid JSON: $file"
    return 0
  else
    echo "✗ Invalid JSON: $file" >&2
    return 1
  fi
}

CONFIG="infra/k8s/app-config.json"
validate_json "$CONFIG" || { echo "Aborting deploy: invalid config" >&2; exit 1; }

find ./config -name "*.json" | while read -r f; do
  jq . "$f" > /dev/null 2>&1 || echo "INVALID: $f"
done

# Format and overwrite safely using a temp file
tmp=$(mktemp)
jq --indent 2 . config/feature-flags.json > "$tmp" && mv "$tmp" config/feature-flags.json
echo "Formatted config/feature-flags.json"

# Format deployment status from API
DEPLOY_ID="dep_8f3a2b9c"
curl -s \
  -H "Authorization: Bearer $DEPLOY_API_TOKEN" \
  "https://api.deployments.internal/v1/deploys/$DEPLOY_ID" \
  | jq --indent 2 .

# Get formatted + filter to errors only from a monitoring endpoint
curl -s "https://monitoring.internal/api/events?level=error&limit=10" \
  | jq '[.events[] | {id, message, timestamp, service}]' \
  || { echo "Failed to fetch or parse events" >&2; exit 1; }

- name: Validate JSON configs
  run: |
    echo "Validating JSON configuration files..."
    find . -name "*.json" -not -path "*/node_modules/*" | while read -r f; do
      if ! jq . "$f" > /dev/null 2>&1; then
        echo "::error file=$f::Invalid JSON syntax"
        exit 1
      fi
    done
    echo "All JSON files are valid"

#!/usr/bin/env bash
set -euo pipefail
STAGED=$(git diff --cached --name-only --diff-filter=ACM | grep '\.json$' || true)
[ -z "$STAGED" ] && exit 0
for f in $STAGED; do
  jq . "$f" > /dev/null 2>&1 || { echo "Invalid JSON: $f"; exit 1; }
done
echo "JSON validation passed"

# Always quote "$API_RESPONSE" — whitespace in JSON would break an unquoted expansion
echo "$API_RESPONSE" | jq --indent 2 .

payload=$(jq -n \
  --arg env "production" \
  --arg version "$(git describe --tags)" \
  --argjson replicas 3 \
  '{environment: $env, version: $version, replicas: $replicas}')

# Inspect the built payload
echo "$payload" | jq .

# Post it to an API
curl -s -X POST \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer $DEPLOY_API_TOKEN" \
  -d "$payload" \
  "https://api.deployments.internal/v1/deploys"

# Format from a file
python3 -m json.tool config.json

# Control indent width
python3 -m json.tool --indent 2 config.json

# Sort keys alphabetically
python3 -m json.tool --sort-keys config.json

# Format from stdin (e.g., piped from curl)
curl -s https://api.deployments.internal/v1/status | python3 -m json.tool

# Validation with exit code (same semantics as jq)
python3 -m json.tool config.json > /dev/null && echo "valid" || echo "invalid"

# Inline string validation
echo '{"service":"payments-api","healthy":true}' | python3 -m json.tool > /dev/null
echo "Exit code: $?"  # 0 = valid

# macOS
brew install bat

# Debian / Ubuntu (binary may be named batcat — alias if so)
apt-get install -y bat
# alias bat=batcat   # add to ~/.bashrc if needed

# Verify
bat --version  # bat 0.24.0

# Syntax-highlighted JSON in the pager (press q to exit)
bat config/app-config.json

# Disable paging — print directly to terminal
bat --paging=never config/app-config.json

# Pipe jq output through bat for coloured inspection
jq '.database' infra/app-config.json | bat --language=json --paging=never

# -C forces color even when stdout is not a tty (e.g. when piping to less)
jq -C . logs/deploy-response.json | less -R

# --stream emits [path, scalar] pairs as jq reads the input
# Extract all "status" fields from a large log archive without loading it fully
jq -c --stream   'if length == 2 and (.[0][-1] == "status") then .[1] else empty end'   logs/archive-2026-03.json

# NDJSON: one JSON object per line — common in Kafka exports, Fluentd, and Logstash
# -R reads raw lines; fromjson? skips lines that are not valid JSON
jq -c -R 'fromjson? | {id: .request_id, status: .http_status, latency: .duration_ms}'   logs/access-2026-03-13.ndjson > logs/summary.ndjson

# Shell loop alternative — useful when you need per-line error handling
while IFS= read -r line; do
  echo "$line" | jq -c '{id: .request_id, status: .http_status}' 2>/dev/null ||     echo "SKIP: malformed line" >&2
done < logs/access-2026-03-13.ndjson