kh

Python script that helps you keep a tidy known_hosts file

Description

ssh-keyscan outputs one line per address per algorithm, so scanning a host by hostname and IP gives you six messy, duplicated lines. kh merges them into three clean ones with all addresses on each line: hostname first, then private IP, then public IP - keeping your known_hosts deduplicated and readable.

The motivation behind this script was to make it easy to keep a chezmoi-managed known_hosts files tidy, even when reaching thousands of entries. Therefore, the script also works on .tmpl files.

Usage

# Scan a host, print formatted block to stdout
kh add 10.21.181.2
kh add my.server.com -p 2222

# Merge into an existing file (outputs full updated file to stdout)
kh add 10.21.181.2 -f known_hosts > known_hosts.new

# Clean up / deduplicate / enrich an existing file
kh cleanup known_hosts > known_hosts.new

Status messages go to stderr, clean output goes to stdout.