Terminal GuideTerminal Guide

fx

Dev Tools•
macOSLinuxWindows
•Go

Terminal JSON viewer with interactive navigation.

Official Website

Features

InteractiveStreamingJavaScript FunctionsThemes

Installation

Homebrew
brew install fx
npm
npm install -g fx

Why use fx?

fx is a lightweight JSON viewer for the terminal that provides an interactive experience for exploring JSON data. Perfect for debugging APIs, inspecting configuration files, and processing large JSON streams without the overhead of traditional editors.

Interactive Navigation

Navigate JSON structures with arrow keys, expand/collapse nodes, and search through large datasets efficiently.

Streaming Support

Process large JSON files and streams without loading everything into memory. Handles gigabyte-sized datasets.

JavaScript Functions

Apply custom JavaScript filters and transformations to manipulate JSON data directly from the terminal.

Minimal & Fast

Written in Go with no external dependencies. Starts instantly and responds smoothly to user input.

Installation

Installation
# macOS (Homebrew)
brew install fx

# Ubuntu/Debian
curl -sL https://github.com/antonmedv/fx/releases/download/v0.98.1/fx-linux -o fx
chmod +x fx
sudo mv fx /usr/local/bin/

# npm
npm install -g fx

# Cargo
cargo install fx

# Windows
choco install fx

Basic Usage

Viewing JSON Files

Viewing JSON
# View a JSON file interactively
fx data.json

# Pipe JSON from another command
curl -s https://api.github.com/users/github | fx

# View stdin
echo '{"name":"John","age":30}' | fx

# Pretty-print without interaction
fx data.json . | cat

Navigation Controls

KeyAction
↓/↑Navigate down/up
←/→Collapse/expand node
/Search
gGo to line
qQuit

Filtering with JavaScript

Filtering
# Select specific property
curl -s https://api.github.com/users/github | fx .login

# Filter array items
echo '[1,2,3,4,5]' | fx '.[] | select(. > 2)'

# Map transformation
echo '[{"name":"Alice","age":25},{"name":"Bob","age":30}]' | fx '.[] | {name, older: .age + 10}'

# Conditional filtering
curl -s https://api.github.com/repos/github/linguist/issues | fx '.[] | select(.state == "open")'

Common Use Cases

API Response Exploration

API Exploration
# Explore GitHub API response
curl -s https://api.github.com/repos/torvalds/linux | fx

# Browse nested data
curl -s https://api.example.com/users | fx '.[0]'

# Extract specific fields from large response
curl -s https://api.github.com/users/google/repos | fx '.[] | {name, stars: .stargazers_count}'

Data Transformation

Transformations
# Convert to different format
echo '{"users":[{"id":1,"name":"Alice"},{"id":2,"name":"Bob"}]}' | fx '.users | @csv'

# Extract keys
echo '{"a":1,"b":2,"c":3}' | fx 'keys'

# Count items
echo '[1,2,3,4,5]' | fx 'length'

# Group by field
echo '[{"type":"A","val":1},{"type":"B","val":2},{"type":"A","val":3}]' | fx 'group_by(.type)'

Debugging Configuration Files

Config Debugging
# View package.json interactively
fx package.json

# Check Docker config
fx ~/.docker/config.json

# Inspect AWS credentials
fx ~/.aws/credentials.json

# Browse Kubernetes resources
kubectl get nodes -o json | fx

Advanced Features

Streaming Large Files

Streaming
# Process JSONL (newline-delimited JSON)
cat events.jsonl | fx '.ip' --null-input

# Stream large JSON array
fx large-data.json '.[100:110]'

# Filter while streaming
fx huge-file.json '.[] | select(.status == "active")'

Complex Queries

Complex Queries
# Multiple transformations
echo '[{"name":"Alice","scores":[85,90,88]},{"name":"Bob","scores":[75,80,82]}]' | fx '.[] | {name, avg: (.scores | add / length)}'

# Recursive descent
fx package.json '.. | objects | select(has("version")) | .version'

# Conditional object construction
echo '{"users":[{"id":1,"active":true},{"id":2,"active":false}]}' | fx '.users | map(if .active then {id, status: "active"} else empty end)'

Interactive Editing

Editing
# Edit JSON interactively in fx
fx config.json

# Use keyboard shortcuts in fx UI
# Press 'e' to edit current value
# Press 's' to save to file

# Combine with other tools
fx data.json | xargs curl -X POST -d

Common Options

OptionDescriptionExample
-r, --raw-outputOutput raw strings without quotesfx data.json -r '.name'
-c, --compactCompact output (no pretty-print)fx data.json -c
-s, --slurpRead entire input into arrayfx -s '*.json'
-M, --monochromeDisable syntax highlightingfx data.json -M
--null-inputUse null as inputfx --null-input '1 + 1'

Tips

  • •Use fx without arguments to read from stdin. Great for exploring API responses: curl ... | fx
  • •The interactive viewer shows line numbers, making it easier to locate deeply nested values
  • •Unlike jq, fx expressions are standard JavaScript, familiar to most developers
  • •Combine with xargs for additional processing: fx file.json '.urls[]' | xargs curl
  • •Use -c flag for piping output to other tools when you need compact JSON
Written by Dai AokiPublished: 2026-01-20

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