Powerful Command Line Tools for Developers
Posted on Tue 07 June 2016 in Tools
The command line remains the most powerful environment for developers. These specialized tools dramatically expand your debugging, testing, and analysis capabilities.
Curl: The HTTP Swiss Army Knife¶
# Get your public IP
curl ifconfig.me
# Inspect response headers
curl -I https://example.com
# POST with JSON data
curl -X POST -H "Content-Type: application/json" \
-d '{"key":"value"}' https://api.example.com
Main usage: Network data transfer, API testing, HTTP inspection.
Ngrep: Grep for Network Traffic¶
# Filter HTTP traffic by keyword
ngrep -i "password" port 80
# Capture by specific IP
ngrep host 192.168.1.100
# Monitor traffic on specific port
ngrep port 443
Main usage: Network packet analysis, protocol debugging, traffic monitoring.
Netcat (nc): The Networking Swiss Army Knife¶
# Port scanning
nc -zv example.com 1-1000
# Transfer file between servers
# Receiver: nc -l 1234 > received_file
# Sender: nc destination_server 1234 < file_to_send
# Create simple HTTP server
echo "HTTP/1.1 200 OK\n\nHello world" | nc -l 8080
Main usage: Port scanning, file transfer, connectivity testing.
Sshuttle: Easy VPN with SSH¶
# Tunnel all traffic
sshuttle -r user@server 0.0.0.0/0
# Tunnel only a subnet
sshuttle -r user@server 192.168.1.0/24
# Bypass geo-blocking
sshuttle -r remote_server 0.0.0.0/0 --dns
Main usage: Secure tunneling, geo-restriction bypass, protection on public WiFi.
Siege: HTTP Load Bombardment¶
# Simple load test
siege -c 25 -t 60s https://example.com
# Test with multiple URLs
siege -c 50 -t 30s -f urls.txt
# Specific benchmark
siege -c 100 -r 10 https://api.example.com/endpoint
Main usage: Performance testing, HTTP benchmarking, load simulation.
Mitmproxy: Spy on HTTP/S Traffic¶
# Basic proxy
mitmproxy -p 8080
# Transparent mode
mitmproxy --mode transparent
# Save traffic to file
mitmdump -w capture.flow
Main usage: Web application debugging, HTTPS traffic inspection, API analysis.
Typical Workflow¶
# 1. Scan connectivity
nc -zv api.example.com 443
# 2. Analyze response
curl -I https://api.example.com
# 3. Monitor traffic
ngrep -i "api" port 443
# 4. Load test
siege -c 20 -t 30s https://api.example.com
# 5. Detailed debugging
mitmproxy -p 8080
Why Command Line?¶
- Speed: No GUI overhead
- Scriptability: Complete automation
- Flexibility: Combination with pipes and redirects
- Universality: Available on any server
These tools turn your terminal into a complete networking and testing laboratory.
Original source: Somos Apañados