#!/usr/bin/env sh
chttl() {
	chttlhelp(){
		cat <<- _help
chttl — Temporarily override the system's default TTL.
Copyright (C) 2025  Gustavo Domínguez  (GPLv3)
# $0                Set TTL to 65.
# $0 n              Set TTL to n.
# $0 -h|--help|-?   Print this message.

Superuser(root)-level privileges are required.
		_help
	}
	chttldo(){
		if [ "$(uname)" = Darwin ]; then
			sysctl net.inet.ip.ttl="${1:-65}"
		elif [ "$(uname)" = Linux ] ; then
			sysctl -w net.ipv4.ip_default_ttl="${1:-65}"
		elif [ "$(uname)" = FreeBSD ] ; then
			sysctl net.inet.ip.ttl="${1:-65}"
		elif uname | grep -i "bsd"; then
			#sysctl net.inet.ip.ttl=65
			echo "Run 'sysctl net.inet.ip.ttl=65' if you think it's safe"
			echo "for this BSD version (only FreeBSD has been tested.)"
		fi
	}
	case "$1" in
		-h|--help|-?) chttlhelp ;;
		*) chttldo "$1" ;;
	esac
}
chttl "$1"