freeifaddrs - Linux

Overview

The freeifaddrs command provides a structured and consistent method of retrieving interface address information for each interface present on the system. It offers a high-level interface to various networking protocols and file systems, making it comprehensive for network information gathering.

Syntax

freeifaddrs [-v] [-l] <filter> [-p <pattern>]

Options/Flags

  • -v: Verbose mode, prints additional information.
  • -l: Show only local addresses (without broadcast, multicast, or point-to-point).
  • : Filter interfaces by name or address.
  • -p : Filter interfaces based on a regular expression pattern.

Examples

1. Display all interface addresses:

freeifaddrs

2. Show only local IPv4 addresses:

freeifaddrs -l inet

3. Filter interfaces by name:

freeifaddrs eth0

Common Issues

  • Using an invalid filter or pattern can produce unexpected results.
  • Ensuring the system is updated with the latest drivers can prevent errors.

Integration

  • Use the output of freeifaddrs in scripts or programs to gather network information.
  • Combine with other commands like netstat or ping for advanced network diagnostics.

Related Commands

  • ifconfig: Legacy tool for displaying network interface information.
  • ip: Comprehensive network configuration and monitoring tool.
  • route: Command for managing routing tables.