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Network commands enable making HTTP requests, downloading files, and performing DNS lookups from the browser-based terminal.

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HTTP Clients

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curl

Transfer data from or to a server using various protocols. Usage: curl [options] url Options:
  • -X method - HTTP method (GET, POST, PUT, DELETE, etc.)
  • -H header - Add custom header
  • -d data - Send data in request body (auto sets POST)
  • -o file - Write output to file
  • -s, --silent - Silent mode (hide progress)
  • -L, --location - Follow redirects
  • -I, --head - Show headers only
Examples: 
# Simple GET request
curl https://api.example.com/data

# With custom header
curl -H "Authorization: Bearer token123" https://api.example.com/protected

# POST request with data
curl -X POST -d '{"name":"John"}' -H "Content-Type: application/json" https://api.example.com/users

# Save to file
curl -o output.json https://api.example.com/data

# Silent mode
curl -s https://api.example.com/data

# Follow redirects
curl -L https://example.com

# Show headers only
curl -I https://example.com

# Multiple headers
curl -H "Accept: application/json" -H "User-Agent: MyApp/1.0" https://api.example.com
Output example: 
$ curl https://api.github.com/users/octocat
{
  "login": "octocat",
  "id": 1,
  "name": "The Octocat",
  "company": "@github"
}
CORS Note: Browser-based curl requests are subject to CORS policies. The target server must include appropriate CORS headers to allow cross-origin requests: 
Access-Control-Allow-Origin: *
If you encounter CORS errors, the server must be configured to allow requests from your origin.

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wget

Download files from the web. Usage: wget [options] url Options:
  • -O file - Write output to file
  • -q - Quiet mode
Examples: 
# Download file
wget https://example.com/file.zip

# Save with custom name
wget -O myfile.zip https://example.com/download.zip

# Quiet mode
wget -q https://example.com/data.json

# Download to specific location
wget -O /tmp/download.pdf https://example.com/document.pdf
Output example: 
$ wget https://example.com/data.json
Downloading https://example.com/data.json...
Saved to: data.json

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Network Diagnostics

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ping

Test network connectivity and measure latency. Usage: ping [options] host Options:
  • -c count - Number of pings (default: 4)
Examples: 
# Ping host
ping example.com

# Specific count
ping -c 10 example.com

# Ping IP address
ping 8.8.8.8
Output example: 
$ ping -c 4 example.com
PING example.com (93.184.216.34): 56 data bytes
64 bytes from 93.184.216.34: icmp_seq=0 ttl=56 time=12.3 ms
64 bytes from 93.184.216.34: icmp_seq=1 ttl=56 time=11.8 ms
64 bytes from 93.184.216.34: icmp_seq=2 ttl=56 time=12.1 ms
64 bytes from 93.184.216.34: icmp_seq=3 ttl=56 time=12.5 ms

--- example.com ping statistics ---
4 packets transmitted, 4 received, 0% packet loss
round-trip min/avg/max = 11.8/12.2/12.5 ms

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dig

DNS lookup utility for querying DNS servers. Usage: dig [options] domain [type] Query types:
  • A - IPv4 address (default)
  • AAAA - IPv6 address
  • MX - Mail exchange
  • NS - Name servers
  • TXT - Text records
  • CNAME - Canonical name
  • SOA - Start of authority
Examples: 
# Basic lookup
dig example.com

# Specific record type
dig example.com A
dig example.com MX
dig example.com TXT

# IPv6 address
dig example.com AAAA

# Name servers
dig example.com NS

# Short answer
dig example.com +short

# Multiple queries
dig example.com A example.com MX
Output example: 
$ dig example.com A

; <<>> DiG 9.10.6 <<>> example.com A
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12345

;; QUESTION SECTION:
;example.com.                   IN      A

;; ANSWER SECTION:
example.com.            3600    IN      A       93.184.216.34

;; Query time: 45 msec
;; WHEN: Sun Mar 01 12:00:00 UTC 2026
;; MSG SIZE  rcvd: 56
Short output: 
$ dig example.com +short
93.184.216.34

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Working with APIs

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GET request

curl https://api.example.com/users/123

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POST JSON data

curl -X POST \
  -H "Content-Type: application/json" \
  -d '{"username":"john","email":"[email protected]"}' \
  https://api.example.com/users

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Authentication

# Bearer token
curl -H "Authorization: Bearer YOUR_TOKEN" \
  https://api.example.com/protected

# Basic auth
curl -u username:password \
  https://api.example.com/protected

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PUT request

curl -X PUT \
  -H "Content-Type: application/json" \
  -d '{"name":"Updated Name"}' \
  https://api.example.com/users/123

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DELETE request

curl -X DELETE https://api.example.com/users/123

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Download and extract

wget https://example.com/archive.tar.gz
tar -xzf archive.tar.gz

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Common Patterns

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Save API response

curl -s https://api.example.com/data | tee response.json

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Pretty print JSON

curl -s https://api.example.com/data | python -m json.tool

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Check HTTP status

curl -I https://example.com | head -1

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Test API endpoint

curl -X POST -H "Content-Type: application/json" \
  -d @request.json \
  https://api.example.com/test

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Download multiple files

for i in {1..5}; do
  wget https://example.com/file$i.txt
done

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DNS diagnostics

# Check all record types
dig example.com ANY

# Trace DNS resolution
dig example.com +trace

# Query specific DNS server
dig @8.8.8.8 example.com

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Virtual Servers

Lifo supports virtual HTTP servers for local development. Commands can interact with servers started within the terminal: 
# In one terminal tab
node server.js  # Starts server on port 3000

# In another tab
curl http://localhost:3000/api/data
Virtual servers enable full-stack development within the browser environment.

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Error Handling

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Connection errors

curl: (7) Failed to connect to example.com
This may indicate:
  • Invalid URL or hostname
  • Network connectivity issues
  • CORS restrictions (for browser-based requests)

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CORS errors

Note: This may be a CORS restriction. The target server must allow cross-origin requests.
Solution: Ensure the API server includes appropriate CORS headers.

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DNS resolution failures

dig: couldn't get address for 'invalid.domain': not found
Indicates the domain name does not exist or cannot be resolved.

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