update-dns

Bash script to update Dynamic DNS records for multiple domains and hosts via the Namecheap Dynamic DNS API.

Requirements

• bash
• curl

Setup

Copy update-dns.conf.example to update-dns.conf and fill in your domains and passwords. Each line follows the format:

domain|password|host1,host2,host3

• domain — the root domain (e.g. example.com)
• password — the Dynamic DNS password from your Namecheap DNS settings
• hosts — comma-separated list of hosts to update (@ for root, * for wildcard)

Example:

example.com|your-ddns-password|@,*,subdomain

Lines starting with # and blank lines are ignored.

Usage

./update-dns.sh [--dry-run] [--config <file>] <ip>

Argument	Description
<ip>	The IP address to set (required)
--dry-run	Log what would be updated without making any requests
--config <file>	Path to config file (default: update-dns.conf next to the script)

Examples

# Update all records to 1.2.3.4
./update-dns.sh 1.2.3.4

# Dry run to verify what would be updated
./update-dns.sh --dry-run 1.2.3.4

# Use a custom config file
./update-dns.sh --config /etc/update-dns.conf 1.2.3.4

# Pipe output to a log file
./update-dns.sh 1.2.3.4 >> /var/log/update-dns.log

Output

Logs are written to stdout in logfmt format and can be piped to a file if needed.

time=2026-07-08T09:12:29Z level=info domain=example.com msg="Processing domain"
time=2026-07-08T09:12:29Z level=info host=@ domain=example.com msg="Attempting update"
time=2026-07-08T09:12:29Z level=info host=@ domain=example.com msg="Update successful"