How to Test Website Loading Speed in Linux Terminal

Testing website loading speed via the Linux terminal can be done using several command-line tools that measure various performance metrics such as total response time, throughput, and concurrent request handling.

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1. curl (Measure Connection Timings)

Installation: Preinstalled on most systems.
Use Case: Basic metrics like DNS lookup, SSL handshake, and total time.

curl -s -w "\n\nTiming Details:\n-----------------\nDNS Lookup: %{time_namelookup}\nConnect: %{time_connect}\nTLS Handshake: %{time_appconnect}\nTTFB (First Byte): %{time_starttransfer}\nTotal Time: %{time_total}\n" -o /dev/null https://example.com

Output:

Timing Details:
-----------------
DNS Lookup: 0.012s
Connect: 0.045s
TLS Handshake: 0.102s
TTFB (First Byte): 0.250s
Total Time: 0.350s

• -o /dev/null: Discards the downloaded content (tests speed, not data).
• Key Metrics:
• TTFB (Time to First Byte): Server response time.
• Total Time: Full page/content load time.

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2. ab (Apache Benchmark)

Installation:

# Debian/Ubuntu
sudo apt install apache2-utils

# Fedora/RHEL
sudo dnf install httpd-tools

Use Case: Load testing with concurrent requests.

ab -n 100 -c 10 https://example.com/

• -n 100: Send 100 total requests.
• -c 10: Simulate 10 concurrent users.
• Output includes requests per second, latency distribution, and error rates.

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3. siege (HTTP Load Tester)

Installation:

# Debian/Ubuntu
sudo apt install siege

# Fedora
sudo dnf install siege

Use Case: Stress-test with customizable concurrency.

siege -c 20 -t 30s https://example.com

• -c 20: 20 concurrent users.
• -t 30s: Run for 30 seconds.
• Outputs transaction rate, response time, and success/failure stats.

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4. wget (Download Speed Test)

Installation: Preinstalled on most systems.
Use Case: Measure download speed for large files.

wget --output-document=/dev/null https://example.com/largefile.zip

• Check the terminal output for download speed (e.g., 4.5 MB/s).

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5. httpie (User-Friendly HTTP Client)

Installation:

pip install httpie

Use Case: Detailed breakdown of request phases.

http --verbose --timeout 30 --print=hH https://example.com

• Shows timing for DNS, connection, SSL, and data transfer.

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6. lighthouse (Google’s Performance Audit)

Installation: Requires Node.js.

npm install -g lighthouse

Use Case: Comprehensive performance report (SEO, speed, best practices).

lighthouse https://example.com --view --output=html --output-path=report.html

• Generates an HTML report with scores and recommendations.

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7. speedtest-cli (Network Speed Test)

Installation:

pip install speedtest-cli

Use Case: Check your internet speed first (to rule out local issues).

speedtest-cli

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8. headless Chrome (Puppeteer)

Use Case: Simulate real browser interactions.

1. Install Node.js and Puppeteer:

   npm install puppeteer

2. Create a script (perf-test.js):

   const puppeteer = require('puppeteer');
   (async () => {
     const browser = await puppeteer.launch();
     const page = await browser.newPage();
     await page.goto('https://example.com');
     const perf = await page.metrics();
     console.log('Performance Metrics:', perf);
     await browser.close();
   })();

3. Run it:

   node perf-test.js

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Key Metrics to Analyze

• TTFB (Time to First Byte): Server processing time.
• DNS Lookup: Time to resolve domain to IP.
• SSL Handshake: Overhead for HTTPS.
• Content Load Time: Time to download all assets.

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Tips for Accurate Testing

1. Clear DNS cache:

   sudo systemd-resolve --flush-caches  # systemd

2. Test from multiple locations using tools like curl + proxies.
3. Run tests multiple times to average results.
4. Test during peak vs. off-peak hours.

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Summary Table

Tool	Use Case	Key Feature
curl	Basic timing metrics	TTFB, DNS, TLS breakdown
ab	Load testing	Concurrent requests
siege	Stress testing	Simulate real-world traffic
lighthouse	Performance audit	SEO, accessibility, best practices
headless	Real browser simulation	Render time, JavaScript metrics