getIps.sh

A bash script that resolves hostnames to their IPv4 and IPv6 addresses using DNS lookups.

Description

This script reads a list of hostnames from an input file and performs DNS lookups to find their corresponding IPv4 and IPv6 addresses. The results are written to an output file in a tab-separated format.

Usage

./getIps.sh <input_file> <output_file>

Arguments

input_file: Path to a text file containing hostnames (one per line)
output_file: Path where the results will be written

Example

./getIps.sh hosts.txt results.txt

Input Format

The input file should contain hostnames, one per line:

google.com
github.com
stackoverflow.com

Output Format

The output file will contain tab-separated values with the following columns:

hostname    IPv4_address    IPv6_address

Example output:

google.com    142.250.191.14    2a00:1450:4001:80e::200e
github.com    140.82.112.4      N/A
stackoverflow.com    151.101.1.69    N/A

Features

Resolves both IPv4 (A records) and IPv6 (AAAA records) addresses
Handles empty lines in input file gracefully
Shows "N/A" for addresses that cannot be resolved
Clears previous output file before writing new results
Provides usage information if incorrect arguments are provided

Requirements

dig command (part of dnsutils package)
Bash shell

Installation

Make the script executable:

chmod +x getIps.sh

Error Handling

The script will exit with an error if the wrong number of arguments is provided
Empty lines in the input file are automatically skipped
DNS resolution failures are handled gracefully (shows "N/A")