Small BASH script which iterates over all hosts defined in SSH config and tries to ssh-copy-id your SSH ID to all of them.

ssh-multi-copy-id.sh

#!/bin/bash

cd $(dirname $0)

CONF_PATH=~/.ssh/config

function title() {
	echo "█ $1"
}

function info() {
	echo "  $1"
}

function err() {
	echo "! Error: $1"
}

title "SSH ID Copy Tool Thingie, Premysl Karbula, 2018"

if [[ ! -f "$CONF_PATH" ]]; then
	err "No SSH config found at "$(realpath $CONF_PATH)
	exit 1
fi

info "Using config at "$(realpath $CONF_PATH)

grep --color=never -E '^Host ' $CONF_PATH | while read LINE; do

	HOST=$(echo "$LINE" | sed -e 's/Host\s*//g')

	if [[ "$HOST" == "*" ]]; then
		continue
	fi

	title "SSH host '$HOST' ... "

	# Dry-run to detect if key is already present.
	# Empty string is returned if key IS present.
	DRY_RUN=$(ssh-copy-id -o ConnectTimeout=5 -n $HOST 2>&1)

	NOT_PRESENT=$(echo "$DRY_RUN" | grep "Would have added")
	HAD_TIMEOUT=$(echo "$DRY_RUN" | grep "Connection timed out")

	if [[ ! -z "$HAD_TIMEOUT" ]]; then
		info "Timeout."
		continue
	fi

	if [[ -z "$NOT_PRESENT" ]]; then
		info "Already there."
		continue
	fi

	info "Not present. Copying ..."
	ssh-copy-id $HOST

done

title "Done."