CONNECTIVITY_CHECKING.md

Connectivity Checking

Overview

The ci command (connectivity info) is the primary tool for checking internet connectivity. It provides a simple true/false indication of whether both DNS and TCP connectivity are working.

Basic Usage

Check if internet is available:

wifi-wand ci

Output:

Connected to Internet: true

Or if not connected:

Connected to Internet: false

Using in Scripts

The ci command is specifically designed for use in shell scripts where you need a simple connectivity check:

#!/bin/bash
# Check if internet is available before proceeding
if wifi-wand ci | grep -q true; then
  echo "Internet is available - proceeding with upload"
  # Do something that requires internet
  curl https://example.com/upload --data @file.txt
else
  echo "Internet is unavailable - will retry later"
  # Queue the operation for later
  exit 1
fi

Exit Codes for Automation

You can also use the exit code (though the above pattern with grep is simpler):

#!/bin/bash
# Retry operation until internet is available
while ! wifi-wand ci | grep -q true; do
  echo "Waiting for internet..."
  sleep 10
done

echo "Internet is now available!"
# Proceed with network operations

Comparing Connectivity Tools

Command	Use Case	Output	Speed
ci	Simple connectivity check	true/false	Fast
status	Full network summary	Multi-field status	Several seconds
info	Detailed network info	Complete data	Several seconds

Use ci when you just need to know "is the internet working?". Use status when you need the complete picture of your network state.

Understanding the Results

ci checks two things:

1. DNS Resolution: Can the system resolve domain names?
2. TCP Connectivity: Can the system establish TCP connections?

Internet is considered available only when both are working.

Examples

Wait for Internet to Come Back Online

#!/bin/bash
echo "Internet went down, waiting for it to come back..."

while ! wifi-wand ci | grep -q true; do
  sleep 5
done

echo "Internet is back!"
mail -s "Internet restored" user@example.com < /dev/null

Run a Task Only When Internet is Available

#!/bin/bash

if wifi-wand ci | grep -q true; then
  # Do something that requires internet
  git push origin main
  echo "Code pushed successfully"
else
  echo "No internet - skipping push"
  exit 1
fi

Monitor Connectivity in a Loop

#!/bin/bash

while true; do
  if wifi-wand ci | grep -q true; then
    echo "$(date): Internet available"
  else
    echo "$(date): Internet unavailable"
  fi
  sleep 30
done

Timeouts

Like the status command, ci uses intentionally long timeouts (several seconds on macOS) to avoid false positives from temporary network slowdowns. This means each check takes several seconds to complete.

If you need to check connectivity frequently, be mindful that each check will block for several seconds. Use appropriate sleep intervals between checks when polling in a loop.